Headache with Nausea: Causes and When to Worry

Headache with Nausea or Vomiting — Causes, What Helps and When to Worry

Why a headache can make you feel sick, what usually causes it, what helps, and the warning signs that need urgent care. Explained by a Sydney neurologist.

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When a Headache with Nausea or Vomiting Needs Urgent Care

Most headaches that come with nausea are migraine, which is common and not dangerous. A few patterns need care straight away, so they come first.

Call 000 — or go to an emergency department — if

a headache comes on suddenly and severely and reaches its worst within a minute (the worst headache of your life), even if it then eases
a very high blood pressure reading (a top number of 180 or more, or a bottom number of 120 or more) comes with chest or back pain, shortness of breath, vomiting, problems with your eyesight, confusion or a seizure: call 000 straight away
your blood pressure is still very high when you measure it again after 5 minutes of sitting quietly, and you have a headache
the headache comes with fever and a stiff neck, a rash that does not fade when pressed, confusion or unusual drowsiness
you are over 50 with a new headache, or a change in your usual headaches, and you notice blurring, double vision, or sight that dims or goes dark in one eye, even if it lasts only a few minutes
the headache comes with sudden loss or dimming of vision (even if brief), double vision, a new drooping eyelid or one pupil larger than the other, slurred speech, sudden severe dizziness or unsteadiness, or numbness, weakness or drooping of the face, an arm or a leg
an eye becomes painful and red, with blurred vision, halos (coloured rings) around lights, or nausea and vomiting
the headache started after a head injury and is getting worse, comes with vomiting, drowsiness or confusion, or you take blood-thinning medicine
the headache comes with a seizure
you think carbon monoxide could be the cause (other people in your home, or your pets, are unwell at the same time, you feel better away from home, or a gas heater, a fuel-burning appliance, or an engine or barbecue is being used indoors or in a garage): get everyone out into fresh air now and turn the appliance off if it is safe to; call 000 if anyone is dizzy, faint, confused, drowsy or unconscious, and otherwise call the Poisons Information Centre on 13 11 26 straight away; do not go back inside until you have had advice
after time in the heat, or hard exercise on a hot day, the headache comes with confusion, slurred speech, poor coordination, a seizure or collapse (possible heatstroke): call 000, and start cooling the person while you wait
you vomit blood, or what looks like coffee grounds, or vomit green fluid with a swollen or painful tummy, or have severe tummy pain
you are more than 20 weeks pregnant or had a baby in the last 6 weeks and have a severe headache, a headache that does not get better with simple pain relief, blurred vision or flashing lights, sudden swelling of the face, hands or feet, pain under the ribs or in the upper tummy, vomiting with a headache, or a reading of 160/110 or more: go to your maternity unit or an emergency department now; call 000 for a seizure, trouble breathing or chest pain
you have a spinal cord injury at mid-chest level or higher and get a sudden, pounding headache, often with sweating or flushing above the injury: sit upright with your legs down, loosen anything tight, check your bladder, catheter and bowel, and follow your own dysreflexia plan if you have one; call 000 if it does not settle within a few minutes or you cannot find the cause

A sudden, explosive headache, wherever it is felt, can mean bleeding around or into the brain (a subarachnoid or intracerebral haemorrhage). A very high reading with chest or back pain or shortness of breath can mean the heart or the main artery from the heart is under strain; with vomiting, problems with eyesight, confusion or a seizure, it can mean the pressure is affecting the brain (hypertensive encephalopathy). A very high reading with a headache needs checking in an emergency department, because only tests can show whether the pressure is harming the brain, heart, eyes or kidneys. In someone over 50, a new headache with a change in vision can mean giant cell arteritis is cutting off the blood supply to the eye: treated the same day, sight can usually be saved, but sight that is lost rarely comes back. Weakness, numbness or drooping of the face, trouble speaking, sudden unsteadiness or a sudden loss of vision can mean a stroke. Double vision, a new drooping eyelid or a change in the size of one pupil can mean pressure on a nerve from a bulging blood vessel (an aneurysm) or a tear in the wall of an artery in the neck (a dissection). A painful red eye with blurred vision and halos can mean a sudden rise in the pressure inside the eye (acute angle-closure glaucoma), which can permanently damage sight if it is not treated quickly. After a head injury, bleeding inside the skull can build up over hours, sometimes after a spell of feeling well. Fever with a stiff neck, or a rash that does not fade when pressed, can mean meningitis. A seizure with a headache needs urgent checks for a cause in the brain. Carbon monoxide, a poisonous gas from burning fuel that you cannot see or smell, causes a headache, nausea and vomiting, and in larger amounts dizziness, fainting and loss of consciousness. Heatstroke, when the body overheats, is a medical emergency that can affect the brain. Vomiting blood (red, or like coffee grounds), green fluid with a swollen or painful tummy, or severe tummy pain can mean bleeding or a blockage in the stomach or bowel; a little yellow-green fluid after vomiting many times on an empty stomach is common in a migraine attack or a stomach bug. In pregnancy or after a birth, a severe headache can be the first sign of pre-eclampsia, a condition of high blood pressure in pregnancy that can lead to seizures; after a spinal cord injury, a pounding headache can be autonomic dysreflexia, a sudden surge in blood pressure set off by something below the injury, such as a full bladder. In both, lower readings than 180/120 count: in pregnancy, 140/90 is high and 160/110 is severe; after a spinal cord injury, a rise in the top number of 20 to 40 or more above your usual reading matters, and 130/90 can already be high. All need urgent treatment. If you have migraine, your usual aura (shimmering or zigzag lines that spread slowly over several minutes and clear within an hour) does not need 000 on its own, and nor do the eye signs of attacks a doctor has already diagnosed as cluster headache (a red, watering eye, a drooping eyelid or a smaller pupil). A first cluster-like attack, a first aura after 50, or an attack or aura that is different from your usual ones needs an emergency department the same day; call 000 if it comes with a new drooping eyelid, one pupil larger than the other, or a very high reading. In the same way, vomiting in your usual migraine attack does not need 000 on its own; with a very high reading, or any other sign in this list, it does, and if you are more than 20 weeks pregnant or had a baby in the last 6 weeks, vomiting with a headache needs your maternity unit or an emergency department now, even in a usual attack. If a doctor has diagnosed vestibular migraine, your usual spells of dizziness, even sudden ones, do not need 000 on their own; a spell unlike your usual ones needs an emergency department the same day, and 000 if it is sudden and severe or comes with double vision, slurred speech, trouble walking, or numbness or weakness. Remember FAST: Face drooping, Arm weakness, Speech difficulty, Time to call 000.

See your GP the same day if

you are vomiting and cannot keep fluids down, have signs of dehydration (passing little or no urine, very dark urine, or feeling dizzy or faint when you stand up), or the vomiting has gone on for more than 2 days, or you are vomiting and have a weakened immune system: see your GP straight away, or go to an emergency department
a migraine attack has lasted more than 3 days
you have a first spell of dizziness or spinning (vertigo) with a headache, or a spell unlike your usual ones: go to an emergency department the same day; call 000 if it is sudden and severe, or comes with double vision, slurred speech, trouble walking, or numbness or weakness
it is a new headache, or a change in your usual headaches, and you are over 50, especially with a new tender scalp that does not go away, pain in the jaw when you chew that eases when you stop, aching shoulders, or feeling generally unwell; with any change in your vision, see the list above
a new headache on one side, unlike your usual headaches, comes with new pain on the same side of the neck, or with a ringing or whooshing in the ear that started suddenly, especially after a neck injury, a sudden twist or stretch of the neck, or neck manipulation: go to an emergency department the same day; with a new drooping eyelid or one pupil larger than the other, or any other sign in the list above, call 000
a first attack of severe pain in or around one eye or temple, with a red or watering eye or a blocked or runny nostril on that side, or, if you have cluster headache, an attack unlike your usual ones: go to an emergency department the same day; with a new drooping eyelid or one pupil larger than the other, call 000
a rash of small blisters appears on one side of the forehead, temple or scalp, often after 2 or 3 days of burning or tingling pain there; if the rash reaches the tip of the nose, or the eye becomes red, painful or blurred, go to an emergency department the same day
your blood pressure is still very high (a top number of 180 or more, or a bottom number of 120 or more) when you measure it again, even if the headache has gone and you feel well (in pregnancy and after a spinal cord injury, lower readings count: see above)
the headache is getting steadily worse over days or weeks
the headache is worse when you lie down, or is worst on waking and comes with vomiting or blurred vision
the headache is brought on by coughing, sneezing, laughing or straining, or comes with a whooshing sound in the ears in time with your heartbeat (if it started suddenly with a new headache on one side, go to an emergency department the same day: see above)
you have a fever with the headache
it is a new headache, or a change in your usual headaches, and you have, or have had, cancer, or you have a weakened immune system
you are pregnant or have had a baby in the last 6 weeks, or a reading taken from 20 weeks of pregnancy to 6 weeks after the birth is 140/90 or more: contact your midwife, maternity unit or GP the same day; with blurred vision or sudden swelling of the face, hands or feet, contact your maternity unit or go to hospital now

Vomiting that will not stop can dry you out (dehydration), and fluids through a drip in hospital may be needed; a migraine attack that lasts more than 3 days needs a doctor's help to stop it. A first spell of dizziness or spinning with a headache is often migraine, but a stroke at the back of the brain can look the same and is easily missed, so the first one is checked that day. A tear in the wall of an artery in the neck (a dissection) can lead to a stroke in the days after it starts, so it needs a scan of the neck arteries that day. A first attack of severe pain around one eye with a red, watering eye is often cluster headache, but a few conditions that need treatment can look the same, so the first one is checked that day. Shingles near the eye can damage sight, and its treatment works best when it is started early. Some migraine attacks begin on waking with nausea or vomiting; what needs checking is a headache that is worse when you lie down, or a new headache, or a change in your usual headaches, that keeps coming back on waking with vomiting or blurred vision, or one that is getting steadily worse, because these can mean raised pressure inside the head. In someone over 50, a new tender scalp that does not go away, or jaw pain on chewing, can mean giant cell arteritis, an inflammation of the arteries of the head that can threaten sight, so it is checked that day. A headache brought on by coughing or straining can come from a problem at the back of the brain, so it is checked if a doctor has not already looked into it. Fever can mean an infection. Cancer, a weakened immune system, and pregnancy or a recent birth each make some serious causes more likely, so the bar for checking is lower. A very high reading without symptoms is rarely an emergency, but it needs a doctor that day to start or adjust treatment. The other items are explained further down this page. If you cannot see your GP that day, go to an emergency department. If something matches both lists, follow the 000 list.

Where most people sit

These patterns are uncommon. Most headaches with nausea are migraine; others come with a stomach bug or a viral illness, a hangover, heat exhaustion, or too little food or fluid. None of these damages the brain, and all can be treated. If you are worried about a brain tumour: in a large UK study of family-doctor records, fewer than 1 in 1,000 people who saw their GP with a headache were later found to have one, and tumours usually cause other symptoms too, such as weakness, seizures, confusion, or a headache that gets steadily worse over weeks. These figures do not apply if you have, or have had, cancer, or have a weakened immune system: see your GP the same day about a new headache.

If the Problem Is in Your Head, Why Does Your Stomach Feel It?

It often follows the same path. A dull ache starts behind one eye in the afternoon, the smell of someone's lunch suddenly seems unbearable, and by evening you are lying in a dark room, feeling sick, perhaps vomiting. It is natural to blame something you ate, or to wonder whether feeling sick means the headache is more serious. But if the stomach were the problem, why would the nausea come with the headache, attack after attack, and go when the headache goes?

For most people the answer is migraine, and the nausea is part of the attack, not a separate illness. The international classification of headache disorders, the rulebook neurologists use, names two kinds of symptom that come with a migraine headache: nausea or vomiting, and a dislike of both light and noise. A migraine needs at least one of them. In a large US population study of 6,488 people with migraine, about half felt sick in at least half of their attacks, and the nausea added to the disability of migraine in its own right. In a US telephone survey of 500 people with migraine, more than 9 in 10 had felt sick in an attack at some time, and almost 7 in 10 had vomited. Headache Australia notes that the nausea and vomiting can be more distressing than the pain itself.

The nausea starts in the brain, not the stomach. In a brain-scanning study in London, people who felt sick in the early, warning phase of a migraine attack, before any pain, showed activity in the parts of the brainstem that control nausea and vomiting, which was absent in those who did not feel sick; the researchers concluded that the nausea of migraine is driven by the brain. The stomach can be affected too. In small studies, it emptied more slowly during attacks, which may delay how quickly a tablet is absorbed, although a review found that absorption is usually not impaired. The bigger problem is practical: in the US survey, nearly a third of the people with nausea, and more than 4 in 10 of those who vomited, said it got in the way of taking their tablets.

Nausea does not always wait for the pain. It can arrive before the headache, as a warning symptom, in about a quarter of people with migraine, and in a US headache centre study of 827 people, 68 in 100 had symptoms after the headache had gone, lasting about a day on average: mostly tiredness, and a stomach upset in about 1 in 12. So nausea with a headache usually tells you what kind of headache it is, not that something is wrong with your stomach, and not that the headache is dangerous. What matters more is the pattern: whether this is your usual kind of headache, how it started, and what else comes with it.

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Nausea, and sometimes vomiting, is part of many migraine attacks. Migraine is common, does not damage the brain, and can be treated. Vomiting in your usual attacks does not, on its own, make a headache more serious; the warning signs are in the lists at the top. If you are more than 20 weeks pregnant or had a baby in the last 6 weeks, vomiting with a headache needs your maternity unit or an emergency department now, even in a usual attack.

Migraine, Tension-Type or Something Else? How Nausea Helps Tell Them Apart

Whether a headache comes with nausea is one of the first things a neurologist asks about, because it helps tell the common headaches apart. No single feature proves one, but together they point to it. The table compares five of them.

Swipe the table sideways to compare all five →

Feature	Migraine	Vestibular migraine	Tension-type headache	A stomach bug (gastroenteritis)	Hangover
What it feels like	Throbbing; moderate to severe; often on one side; worse with routine activity	Dizziness, spinning or unsteadiness, with or without a migraine headache	Pressing or tightening, like a band; mild to moderate; usually on both sides	A headache alongside the stomach symptoms	Throbbing or pressing, on both sides; worse with activity
Nausea or vomiting	Common: nausea or vomiting, or a dislike of both light and noise, is part of the diagnosis	Common, though not part of the diagnosis; moving the head can bring on dizziness with nausea	None, or only mild nausea in the long-lasting (chronic) form; vomiting points away from it	Vomiting, often with diarrhoea	Common
How long	4 to 72 hours	5 minutes to 3 days	30 minutes to 7 days	The vomiting usually lasts 1 to 2 days	Starts 5 to 12 hours after drinking; gone within 3 days
Other clues	A dislike of light and noise; sometimes an aura	Migraine now or in the past; a dislike of light and noise, or an aura, in many spells	Not worse with routine activity; light or noise may bother you, but not both	Others around you unwell; stomach cramps; sometimes a fever	After drinking alcohol

Migraine. By far the most common cause of a headache with nausea: about 1 in 7 people worldwide have migraine. The headache usually throbs, is moderate to severe, is often on one side and is worse with routine activity, and it lasts 4 to 72 hours. Nausea or vomiting, or a dislike of light and noise, comes with it. Stress, missed meals, poor sleep and hormonal changes are among its common triggers. Some people see flashing lights or zigzag lines before the headache: see migraine aura, and our migraine overview.
Vestibular migraine. A form of migraine in which the main symptom is dizziness, spinning (vertigo) or unsteadiness, often with nausea, in someone who has, or has had, migraine. The spells last from 5 minutes to 3 days, roughly a third each lasting minutes, hours or days, and they can come with or without a headache. Moving the head, or busy moving scenes such as traffic, can bring them on, and many people with it are prone to motion sickness. In a German population study, about 1 in 100 adults had had vestibular migraine at some time, but only 1 in 5 of those who saw a doctor about it were told what it was. The classification lists it in its appendix, the section for conditions still being refined, so it is diagnosed from the pattern of the spells once other causes of dizziness have been considered. Read more about vestibular migraine symptoms.
Tension-type headache. The most common headache of all: a pressing or tightening ache, like a band, usually on both sides, mild to moderate, and not made worse by routine activity. By definition it comes with no nausea or vomiting; in its long-lasting form, on 15 or more days a month, only mild nausea is allowed. So a "tension headache" that makes you vomit is probably not a tension-type headache, and is often migraine. Many people have both, which is why a headache diary helps. Read more about tension headache.
Attacks of vomiting linked with migraine. In cyclic vomiting syndrome, attacks of intense nausea and vomiting, at least four times an hour, last from an hour to 10 days and come back at fairly regular intervals, with complete wellness in between. It affects children and adults, and is closely linked with migraine. In abdominal migraine, attacks of tummy pain with nausea or vomiting last 2 to 72 hours, without a headache; it is seen mainly in children, most of whom go on to have migraine headaches later. Both need a doctor to rule out a problem in the stomach or bowel first.
Too much pain relief. Pain relief taken on too many days a month can itself keep headaches going: see medication overuse headache.

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The table is a guide, not a diagnosis. Migraine is by far the most common reason for a headache with nausea, and many people with migraine have tension-type headaches too. Sorting out which headache, or headaches, you have is the main job of a consultation, and each has its own treatment.

Everyday Causes: Stomach Bugs, Heat, Alcohol and Missed Meals

Plenty of headaches with nausea have nothing to do with migraine, and most settle within a day or two.

A stomach bug or food poisoning (gastroenteritis). Vomiting, often with diarrhoea and stomach cramps, and sometimes a headache and a fever. The vomiting usually lasts 1 to 2 days. Sip clear fluids every 5 to 10 minutes. See your GP if you have a fever, frequent vomiting or diarrhoea, blood or mucus in your poo, tummy pain that is getting worse, or signs of dehydration (see the list at the top). Severe tummy pain, or vomiting blood or green fluid with a swollen or painful tummy, needs 000 (see the list at the top).
Flu, COVID-19 and other viral illnesses. A headache, aches and nausea are common with a fever. A fever with a headache needs your GP the same day; a fever with a stiff neck, a rash that does not fade when pressed, or confusion needs 000.
Too little fluid (dehydration). Thirst, a dry mouth, dark urine, dizziness when you stand up, and a headache. It can follow vomiting, a hot day, exercise, or simply not drinking enough, and it can keep itself going: nausea makes it hard to drink, and too little fluid can bring on a headache and dizziness. Sip fluids little and often; after vomiting, an oral rehydration solution from a pharmacy replaces salts as well as water.
Heat (heat exhaustion). After time in the heat, a headache with nausea or vomiting, dizziness or fainting, heavy sweating, thirst, weakness or muscle cramps. Move to a cooler place, lie down, loosen your clothing and sip water or an oral rehydration solution. If you do not improve, see a doctor or call healthdirect on 1800 022 222; if someone faints and does not come round quickly, call 000. Confusion, slurred speech, poor coordination, a seizure or collapse can mean heatstroke, which needs 000 (see the list at the top).
Alcohol. The morning-after headache is one of the most common headaches with a known outside cause: it starts 5 to 12 hours after drinking, often throbs or is worse with activity, and goes within 3 days. Nausea, shakiness, diarrhoea and tiredness often come with it. In people with migraine, even a small amount of alcohol can sometimes bring on a headache.
Missing your usual coffee (caffeine withdrawal). In people who have caffeine every day, stopping can bring on a headache, sometimes with nausea. In experiments, about half of regular caffeine users got a headache when they stopped, starting 12 to 24 hours later and lasting 2 to 9 days. A headache on a day you miss or delay your usual coffee, tea or cola can be this.
Missed meals (fasting). Going 8 hours or more without food can bring on a headache that eases after eating. In people with migraine, missing a meal is a common trigger for an attack.
Travel. Motion sickness in a car, boat or plane brings nausea, and people with vestibular migraine are often prone to it. At high altitude, above about 2,500 metres, a headache with nausea, loss of appetite, tiredness or dizziness can be acute mountain sickness; it settles within a day of going back down.
Pregnancy. Nausea is most common between weeks 6 and 14 of pregnancy. Any headache in pregnancy, or in the 6 weeks after a birth, needs your midwife, maternity unit or GP the same day, and if you are vomiting and cannot keep fluids down, see your doctor straight away. After 20 weeks, a headache with vomiting, blurred vision, pain under the ribs or sudden swelling can be pre-eclampsia: go to your maternity unit or an emergency department now (see the list at the top).
A knock to the head (concussion). A headache, nausea and vomiting are common after a head injury. Rest for the first 24 to 48 hours, and do not drive or drink alcohol. A headache after a head injury that is getting worse, or comes with vomiting, drowsiness or confusion, needs 000 (see the list at the top).
Medicines. Some medicines, including some taken for headaches, can cause nausea or a headache as a side effect. If a headache with nausea started with a new medicine, ask your pharmacist or doctor, and do not stop a prescribed medicine without advice.

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These everyday causes are common and usually settle within a day or two with fluids and rest. The things to watch for are a headache that keeps getting worse, vomiting that will not stop or leaves you unable to keep fluids down, and anything in the lists at the top.

When a Headache with Nausea Has a Serious Cause

A search for a headache with vomiting often turns up the frightening possibilities first. They are rare, and nearly all come with a clue that sets them apart. Vomiting on its own rarely tells them from a migraine; the clue usually does.

Carbon monoxide poisoning. Carbon monoxide is a poisonous gas that you cannot see, taste or smell. It comes from burning fuel: a faulty gas heater, or a barbecue, outdoor heater, generator or engine used indoors or in a garage, even with the doors or windows open. Its most common symptoms are a headache, nausea, vomiting and weakness, so it is easily mistaken for flu: in a small emergency department study in winter, 7 of 37 people who came in with a headache had raised carbon monoxide levels, and in none of them had it been suspected; larger, more recent studies found far fewer. In the classification, the more carbon monoxide in the blood, the worse the headache: nausea, vomiting and blurred vision come with heavier exposure, and at the highest levels people become drowsy or lose consciousness. The most reliable clue is other people in the home, or pets, unwell at the same time; feeling better away from home is another. Babies, pregnant women, older people and people with heart problems are most at risk. If you suspect it, get everyone out into fresh air and turn the appliance off if it is safe to; call 000 if anyone is dizzy, faint, confused, drowsy or unconscious, and otherwise call the Poisons Information Centre on 13 11 26 straight away. Do not go back inside until you have had advice.
Bleeding around the brain (subarachnoid haemorrhage). A sudden, explosive headache that reaches its worst within a minute. It can be the only symptom, and it is missed at first in a quarter to a half of people, most often mistaken for migraine. Vomiting does not tell the two apart; the sudden start does. Call 000, even if the headache then eases.
Meningitis, an infection of the coverings of the brain. A headache with fever, a stiff neck, nausea and vomiting, a dislike of bright light, drowsiness or confusion, and sometimes a rash of red or purple spots that do not fade when pressed. It can begin like flu, and not everyone has every sign: in a Dutch nationwide study of 696 cases of bacterial meningitis in adults, only 44 in 100 had all three of fever, a stiff neck and confusion, but 95 in 100 had at least two of a headache, fever, a stiff neck and confusion. It is a medical emergency: go to an emergency department or call 000.
Raised pressure inside the head. A headache that is worse in the morning or when lying down, gets steadily worse over days or weeks, and comes with nausea or vomiting, can mean pressure is building up inside the head, for example from a blockage of the fluid pathways, a clot in the veins of the brain, or, rarely, a tumour. The classification notes that the full picture of a severe morning headache with nausea and vomiting is not how most tumours show, though it is more likely when pressure is raised; a headache that keeps getting worse matters more. In a New York series of 111 people with brain tumours, the headaches were most often like tension-type headache, and the clues were nausea or vomiting, an abnormal examination, or a clear change in the usual headache pattern. Raised pressure of the fluid around the brain without a tumour (idiopathic intracranial hypertension) can also cause a whooshing sound in the ears in time with the heartbeat and swelling at the back of the eyes, and is most common in women of child-bearing age. All need your GP the same day, because some can affect sight.
A head injury. Nausea and vomiting are common after a knock to the head, but bleeding inside the skull can build up over hours, sometimes after a spell of feeling well. In two large North American studies of people with minor head injuries, vomiting was one of the signs that picked out those who needed a scan. Call 000 for a headache after a head injury that is getting worse, or comes with vomiting, drowsiness or confusion, or if you take blood-thinning medicine.
A very high blood pressure. A top number of 180 or more, or a bottom number of 120 or more, with a headache and vomiting, confusion, problems with eyesight or a seizure, can mean the pressure is affecting the brain (hypertensive encephalopathy): call 000. In pregnancy and after a spinal cord injury, lower readings count (see the list at the top). See headache with high blood pressure.
Acute angle-closure glaucoma. A sudden rise in the pressure inside one eye: pain in and around the eye, a red eye, blurred vision, halos (coloured rings) around lights, and often nausea and vomiting. It is easily mistaken for a headache: in a London series of 38 people, the doctor who first saw them recognised it in only 4 in 10, and a wrong diagnosis delayed treatment by almost 6 days on average. It can permanently damage sight, so a painful, red eye with blurred vision or halos around lights needs 000 or an emergency department straight away.
Pre-eclampsia. From 20 weeks of pregnancy until 6 weeks after the birth, a severe headache, vomiting, blurred vision or flashing lights, pain under the ribs, or sudden swelling of the face, hands or feet can be pre-eclampsia, a condition of high blood pressure in pregnancy that can lead to seizures. Go to your maternity unit or an emergency department now; call 000 for a seizure, trouble breathing or chest pain.
A stroke. A stroke in the cerebellum, the balance centre at the back of the brain, often starts with dizziness, nausea and vomiting, unsteadiness and a headache, so it is easily missed, and an early scan can look normal. Call 000 for sudden severe dizziness or unsteadiness, double vision, slurred speech, or weakness, numbness or drooping of the face, an arm or a leg, whichever way the headache feels: remember FAST, Face drooping, Arm weakness, Speech difficulty, Time to call 000.
Heatstroke. When the body overheats, a headache with nausea and dizziness can be followed by confusion, slurred speech, poor coordination, seizures and collapse. Call 000, and start cooling the person while you wait: move them somewhere cool, loosen or remove extra clothing, and cool them with cold water. Give cool drinks only if they are fully awake and can swallow.

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These causes are rare, and nearly all come with a clue: a sudden explosive start, fever with a stiff neck or a rash, others at home unwell at the same time, a head injury, a painful red eye, confusion, weakness or trouble speaking, late pregnancy, or a headache that keeps getting worse. Even among people who go to an emergency department with a headache, most do not have a serious cause: in an international study led from Brisbane of 5,293 people, about 1 in 16 did. A headache with nausea that comes and goes in the same way as your usual migraine, with a normal examination, is very rarely any of them.

How Is the Cause of a Headache with Nausea Found?

Mostly from your story and an examination. Tests are for when the pattern raises a question.

Your story. Which came first, the headache or the nausea; whether this is your usual kind of headache; how it started; what else came with it, such as a fever, a rash, a stiff neck, dizziness or a change in your vision; a recent head injury; whether anyone else at home is unwell; alcohol, caffeine, missed meals or heat; whether you could be pregnant; any new medicine; and how often you take pain relief.
The examination. Your temperature, blood pressure and signs of dehydration; the neck; and a full neurological examination, including the eyes and the back of the eyes, where swelling can be a sign of raised pressure inside the head.
A headache diary. A few weeks of a headache diary, noting the nausea and vomiting each time and what you ate and drank, shows the pattern and what sets the attacks off.
A scan, when it will change what happens next. When the pattern fits migraine and the examination is normal, a scan is not needed, and vomiting in a typical migraine attack is not, on its own, a reason for one (if you are more than 20 weeks pregnant or had a baby in the last 6 weeks, vomiting with a headache needs your maternity unit or an emergency department now: see the list at the top). The Australian and New Zealand Association of Neurologists advises against brain scans for long-standing headaches like migraine: in people with recurring migraine or tension-type headaches and a normal examination, a CT or MRI scan finds a significant problem in fewer than 1 in 100, and in some studies as few as 2 in 1,000. Headache Australia makes the same point: when the symptoms are typical and there are no warning signs, a scan is rarely necessary. A scan is arranged when the pattern points away from the common causes: a headache that is new or has changed, one that is getting steadily worse, one that is worse lying down or worst on waking with vomiting, or a warning sign in the lists at the top.
Blood and other tests, when they fit. A blood test for carbon monoxide when it is suspected, done in an emergency department (a normal result does not always rule it out); tests for dehydration and the body's salts after a lot of vomiting; a pregnancy test when pregnancy is possible; and a check of the pressure inside the eye when the eye is painful and red.

What Helps a Headache with Nausea

The treatment depends on the cause, which is why the diagnosis comes first. These help most people.

For a migraine today: treat early. Take simple pain relief at the first sign of the headache, at the dose on the pack, before the nausea builds: in studies of migraine treatment, people who treated early, while the headache was still mild, were more often pain-free than those who waited. Rest in a dark, quiet room. Ask your pharmacist which kind of pain relief suits you, especially if you are pregnant, have other health conditions or take other medicines.
When nausea gets in the way. If you often vomit early in an attack, or feel too sick to swallow tablets, tell your doctor: a medicine for the nausea, or a migraine medicine that does not need to be swallowed, can help, and your doctor can advise which suits you.
Sip, do not gulp. Take small sips of cold, clear fluids, such as water; if you cannot drink, suck ice cubes or an icy pole. After vomiting, an oral rehydration solution from a pharmacy replaces salts as well as water; sports drinks are not recommended for this.
Eat small amounts, often. Plain food such as dry crackers, rice or toast, once you feel able to. Fatty, spicy or very sweet food, and strong smells, can make nausea worse, and fresh air can help.
Keep pain relief to two or three days a week at most, and to fewer than 10 days a month for some kinds. Taking it on too many days (15 or more days a month for simple pain relievers, 10 or more for some others) can itself keep headaches going; ask your pharmacist which yours is, and see medication overuse headache.
Carbon monoxide: prevent it. Have gas heaters checked by a registered gas fitter at least every two years, and never use a barbecue, an outdoor heater, a generator or a petrol engine indoors or in a garage, even with the doors or windows open.
Prevention, when attacks are frequent. A headache diary, regular sleep and meals, enough water, regular exercise and ways to manage stress reduce how often many headaches come. Preventive medicines can reduce how often migraine attacks come; your doctor can advise whether one suits you.

When to See a Neurologist About Headaches with Nausea

Migraine attacks with nausea or vomiting on several days a month, or that stop you working
Attacks in which you vomit before treatment can work, or treatment does not help
Spells of dizziness or spinning with your headaches
Repeated bouts of vomiting, with or without a headache
Headaches on many days a month, or pain relief needed on more than two or three days a week
A headache that has changed, or a new kind of headache (see your GP first; a new headache after 50 needs your GP the same day)
You want a clear diagnosis and a plan

A consultation involves a detailed history, a neurological examination and a plan: working out which headache, or headaches, you have, arranging tests when the result will change what happens next, and coordinating with your GP. Dr Ron Granot trained at Prince of Wales Hospital, Sydney, and sees patients in Bondi Junction. For the wider picture, read our migraine overview.

Frequently Asked Questions

Why do I feel sick when I have a headache? +

Most often because the headache is a migraine. Nausea, and sometimes vomiting, is part of a migraine attack: the areas of the brainstem that control nausea become active during the attack, and the stomach can empty more slowly. The nausea can start before the pain and linger after it. Other common causes are a stomach bug, too little fluid, heat, a hangover, missed meals or a knock to the head. If other people at home, or your pets, are unwell at the same time, you feel better away from home, or a gas heater, a fuel-burning appliance, an engine or a barbecue is being used indoors or in a garage, think of carbon monoxide: get everyone out into fresh air and call the Poisons Information Centre on 13 11 26, or 000 if anyone is dizzy, faint, confused, drowsy or unconscious, and do not go back inside until you have had advice. Call 000 for a headache that comes on suddenly and severely, reaching its worst within a minute, or comes with fever and a stiff neck, confusion, weakness, numbness or drooping of the face, an arm or a leg, trouble speaking, a loss of vision, a painful red eye with blurred vision or halos around lights, or a seizure; for a headache after a head injury that is getting worse or comes with vomiting, drowsiness or confusion; or after any head injury if you take blood-thinning medicine.

When should I worry about a headache with nausea or vomiting? +

Call 000 or go to an emergency department if it comes on suddenly and severely, reaching its worst within a minute, even if it then eases; if it comes with fever and a stiff neck, a rash that does not fade when pressed, confusion, weakness, numbness or drooping of the face, an arm or a leg, trouble speaking, sudden severe dizziness or unsteadiness, a loss of vision, double vision, a new drooping eyelid or one pupil larger than the other, or a seizure; if an eye becomes painful and red, with blurred vision or halos around lights; if you are over 50 with a new headache, or a change in your usual headaches, and notice blurring, double vision or sight that dims or goes dark in one eye; if you have a very high blood pressure reading with the headache (see the list at the top; in pregnancy and after a spinal cord injury, lower readings count); if it started after a head injury and is getting worse, comes with vomiting, drowsiness or confusion, or you take blood-thinning medicine; if, after time in the heat, it comes with confusion, slurred speech, poor coordination or collapse; if you vomit blood, or what looks like coffee grounds, or green fluid with a swollen or painful tummy, or have severe tummy pain; or if carbon monoxide could be the cause and anyone is dizzy, faint, confused, drowsy or unconscious. If other people at home, or your pets, are unwell at the same time, you feel better away from home, or a gas heater, a fuel-burning appliance, an engine or a barbecue is being used indoors or in a garage, get everyone out into fresh air and call the Poisons Information Centre on 13 11 26, and do not go back inside until you have had advice. Vomiting in your usual migraine attacks does not need 000 on its own; with any of these signs, it does. See your GP straight away, or go to an emergency department, if you are vomiting and cannot keep fluids down, have signs of dehydration such as passing little or no urine, have been vomiting for more than 2 days, or are vomiting and have a weakened immune system. Go to an emergency department the same day for a first spell of dizziness or spinning with a headache, or a spell unlike your usual ones; call 000 if it is sudden and severe, or comes with double vision, slurred speech, trouble walking, or numbness or weakness. See your GP the same day if a migraine attack has lasted more than 3 days, or the headache is new after 50, is getting steadily worse, is worse when you lie down, or is worst on waking with vomiting or blurred vision, comes with a fever, or is a new headache and you have, or have had, cancer, or have a weakened immune system. If you are more than 20 weeks pregnant or had a baby in the last 6 weeks, a severe headache, or a headache with vomiting, even in a usual migraine attack, needs your maternity unit or an emergency department now; any other headache in pregnancy or in the 6 weeks after a birth needs your midwife, maternity unit or GP the same day. Other warning signs are in the lists at the top of this page.

Is it serious if a headache makes me vomit? +

Usually not on its own. Vomiting is part of many migraine attacks, so in your usual migraine it is not a warning sign by itself. What matters is whether this headache is your usual kind and what comes with it. Call 000 for a headache with vomiting that came on suddenly and severely, reaching its worst within a minute; that follows a head injury; that comes with fever and a stiff neck, a rash that does not fade when pressed, confusion or drowsiness, weakness, numbness or drooping of the face, an arm or a leg, trouble speaking, a loss of vision, or a painful red eye with blurred vision or halos around lights; or that comes with a very high blood pressure reading (in pregnancy and after a spinal cord injury, lower readings count); and call 000 if you vomit blood, or what looks like coffee grounds, or green fluid with a swollen or painful tummy, or have severe tummy pain. If you are more than 20 weeks pregnant or had a baby in the last 6 weeks, a headache with vomiting needs your maternity unit or an emergency department now, even in a usual migraine attack. See your GP straight away, or go to an emergency department, if you cannot keep fluids down, have signs of dehydration such as passing little or no urine, have been vomiting for more than 2 days, or are vomiting and have a weakened immune system, and see your GP the same day for a headache that is worse when you lie down, or a new headache, or a change in your usual headaches, that keeps coming back on waking with vomiting or blurred vision, or one that is getting steadily worse.

Could a headache with nausea be a brain tumour? +

Very rarely. In a large UK study of family-doctor records, fewer than 1 in 1,000 people who saw their GP with a headache were later found to have a brain tumour. Nausea with a headache is far more often migraine. The classification of headache disorders notes that the full picture of a severe morning headache with nausea and vomiting is not how most tumours show, and that a headache that keeps getting worse matters more; morning headaches with vomiting still need your GP the same day. The headache is the only symptom in between 2 and 16 in 100 people with a brain tumour. Call 000 for weakness, numbness or drooping of the face, an arm or a leg, trouble speaking, a loss of vision or a seizure. See your GP the same day for a headache that gets steadily worse over days or weeks, is worse when you lie down, or is worst on waking with vomiting or blurred vision. These figures do not apply if you have, or have had, cancer, or have a weakened immune system: see your GP the same day about a new headache.

What does a headache with nausea and dizziness mean? +

Often migraine. In vestibular migraine, spells of dizziness, spinning or unsteadiness, often with nausea, last from 5 minutes to 3 days, with or without a headache, in someone who has, or has had, migraine. Too little fluid, heat, a stomach bug, a hangover, motion sickness and a knock to the head can also cause all three. Less often the cause is carbon monoxide, especially if other people at home, or your pets, are unwell at the same time, you feel better away from home, or a gas heater, a fuel-burning appliance, an engine or a barbecue is being used indoors or in a garage: get everyone out into fresh air and call the Poisons Information Centre on 13 11 26, or 000 if anyone is dizzy, faint, confused, drowsy or unconscious, and do not go back inside until you have had advice. Call 000 for sudden severe dizziness or unsteadiness, double vision, slurred speech, trouble walking, or weakness, numbness or drooping of the face, an arm or a leg, because these can be a stroke; for confusion, slurred speech or collapse after time in the heat; and for a headache after a head injury that is getting worse or comes with vomiting, drowsiness or confusion, or after any head injury if you take blood-thinning medicine. A first spell of dizziness or spinning with a headache, or a spell unlike your usual ones, needs an emergency department the same day; call 000 if it is sudden and severe, or comes with double vision, slurred speech, trouble walking, or numbness or weakness. If a doctor has diagnosed vestibular migraine, your usual spells, even sudden ones, do not need 000 on their own; one with double vision, slurred speech, unsteadiness much worse than in your usual spells, or numbness or weakness does.

Can dehydration cause a headache and nausea? +

Yes. Too little fluid can cause a headache, dizziness and tiredness, and vomiting or a hot day makes it worse. It can keep itself going, because nausea makes it hard to drink. Sip cold, clear fluids little and often, or suck ice cubes if you cannot drink; after vomiting, an oral rehydration solution from a pharmacy replaces salts as well as water. Missing meals is also a common migraine trigger. See your GP straight away, or go to an emergency department, if you cannot keep fluids down, pass little or no urine, feel dizzy or faint when you stand up, have been vomiting for more than 2 days, or are vomiting and have a weakened immune system. Call 000 for confusion, unusual drowsiness or a seizure, or a headache that came on suddenly and severely, reaching its worst within a minute.

Could my headache and nausea be carbon monoxide poisoning? +

It is uncommon, but worth thinking of, because carbon monoxide cannot be seen, tasted or smelt. Its most common symptoms are a headache, nausea, vomiting and weakness, so it is easily mistaken for flu. Think of it if other people in your home, or your pets, are unwell at the same time, if you feel better away from home, or if a gas heater, a fuel-burning appliance, or a barbecue, generator or engine is being used indoors or in a garage. Get everyone out into fresh air and turn the appliance off if it is safe to. Call 000 if anyone is dizzy, faint, confused, drowsy or unconscious; otherwise call the Poisons Information Centre on 13 11 26 straight away, and do not go back inside until you have had advice. Babies, pregnant women, older people and people with heart problems are most at risk.

How do I get rid of a headache and nausea? +

It depends on the cause. For a migraine, take simple pain relief early, at the dose on the pack, before the nausea builds (if you are pregnant, ask your pharmacist which kind is safe), and rest in a dark, quiet room; if you often vomit early in an attack, your doctor can advise on a medicine for the nausea, or a migraine medicine that does not need to be swallowed. Sip cold, clear fluids little and often, eat small amounts of plain food when you can, and keep away from strong smells. Keep pain relief to two or three days a week at most, and to fewer than 10 days a month for some kinds (your pharmacist can tell you which), because taking it more often can itself keep headaches going. See your GP straight away, or go to an emergency department, if you cannot keep fluids down, have signs of dehydration such as passing little or no urine, have been vomiting for more than 2 days, or are vomiting and have a weakened immune system. If you are more than 20 weeks pregnant or had a baby in the last 6 weeks, a severe headache, a headache with vomiting, or one that does not get better with simple pain relief, needs your maternity unit or an emergency department now; any other headache in pregnancy or in the 6 weeks after a birth needs your midwife, maternity unit or GP the same day. Call 000 for a headache that comes on suddenly and severely, reaching its worst within a minute, or comes with fever and a stiff neck, confusion, weakness, numbness or drooping of the face, an arm or a leg, trouble speaking, a loss of vision or a seizure.

Important: This page is general health information for adults living in Australia and is not a substitute for individual medical advice. If you have a sudden, severe headache that reaches its worst within a minute, a very high blood pressure reading (a top number of 180 or more, or a bottom number of 120 or more; lower readings count in pregnancy and after a spinal cord injury) with a headache, a headache with a stiff neck and fever, confusion, a headache with weakness, numbness or drooping of the face, an arm or a leg, sudden loss of vision, double vision, slurred speech or sudden unsteadiness, a painful red eye with blurred vision, a headache that is getting worse or comes with vomiting after a head injury, a seizure, dizziness, fainting, confusion, drowsiness or unconsciousness when carbon monoxide could be the cause, confusion or collapse after time in the heat, or, if you are over 50, a new headache with blurring, double vision or dimming of sight, or any other warning sign listed at the top of this page, call 000 or go to an emergency department. If you are more than 20 weeks pregnant or had a baby in the last 6 weeks and have a severe headache, vomiting with a headache, blurred vision or flashing lights, go to your maternity unit or an emergency department now. Diagnosis and treatment decisions are made on an individual basis with your treating doctor.

Sources: the studies and guidelines behind this page

The international classification of headache disorders (sections 1.1, 1.4.1, 1.6.1, 2.1, 2.2, 2.3, 6.2.2, 7.1.1, 7.4.1, 8.1.3, 8.1.4.2, 8.3.1, 9.1.1, 10.1.1, 10.3.3, 10.5 and 11.3.1, and appendix A1.6.6): Headache Classification Committee of the International Headache Society. Cephalalgia 2018;38:1-211. PubMed 29368949
Nausea and vomiting in migraine: Lipton RB, et al. Headache 2013;53:93-103 (the US population study of 6,488 people; PubMed 23148774); Silberstein SD. Headache 1995;35:387-96 (the US telephone survey of 500 people; PubMed 7672955).
Nausea before and after the headache, and where it starts: Maniyar FH, et al. J Headache Pain 2014;15:84 (the London brain-scanning study; PubMed 25471540); Kelman L. Cephalalgia 2006;26:214-20 (the US headache centre study of 827 people; PubMed 16426278).
The stomach during attacks: Aurora SK, et al. Headache 2006;46:57-63 (PubMed 16412152); Yalcin H, et al. Intern Med J 2012;42:455-9 (PubMed 22498119); Tfelt-Hansen PC. Cephalalgia 2017;37:892-901 (the review; PubMed 27330004).
Treating a migraine early: Scholpp J, et al. Cephalalgia 2004;24:925-33 (PubMed 15482353); Cady RK, et al. Headache 2009;49:350-63 (PubMed 19220503); Burstein R, et al. Ann Neurol 2004;55:19-26 (PubMed 14705108).
How common migraine is: Stovner LJ, et al. J Headache Pain 2022;23:34. PubMed 35410119
Vestibular migraine: Neuhauser HK, et al. Neurology 2006;67:1028-33 (the German population study; PubMed 17000973); Çelebisoy N, et al. Clin Neurol Neurosurg 2022;215:107201 (motion sickness; PubMed 35303515).
Cyclic vomiting syndrome: Frazier R, et al. Am J Gastroenterol 2023;118:1157-1167. PubMed 36791365
Alcohol and caffeine: Wiese JG, et al. Ann Intern Med 2000;132:897-902 (PubMed 10836917); Juliano LM, Griffiths RR. Psychopharmacology (Berl) 2004;176:1-29 (PubMed 15448977).
Carbon monoxide: Heckerling PS. Am J Emerg Med 1987;5:201-4 (the US winter headache study; PubMed 3580051); Heckerling PS, et al. Am J Med 1988;84:251-6 (PubMed 3407653); Dolan MC, et al. Ann Emerg Med 1987;16:782-6 (PubMed 3592333); Zorbalar N, et al. Emerg Med J 2014;31:e66-70 (PubMed 24128732); Shin M, et al. Ann Emerg Med 2023;81:309-317 (PubMed 36585319); Jarman H, et al. J Public Health (Oxf) 2023;45:553-559 (PubMed 36721987).
Brain tumours: Hamilton W, Kernick D. Br J Gen Pract 2007;57:695-9 (the UK study of family-doctor records; PubMed 17761056); Forsyth PA, Posner JB. Neurology 1993;43:1678-83 (the New York series of 111 people; PubMed 8414011).
Serious causes in the emergency department (the international study led from Brisbane): Chu K, et al. Emerg Med J 2024;41:368-375. PubMed 38658053
Head injury: Stiell IG, et al. Lancet 2001;357:1391-6 (PubMed 11356436); Haydel MJ, et al. N Engl J Med 2000;343:100-5 (PubMed 10891517).
Meningitis (the Dutch nationwide study): van de Beek D, et al. N Engl J Med 2004;351:1849-59. PubMed 15509818
Stroke in the cerebellum: Edlow JA, et al. Lancet Neurol 2008;7:951-64 (PubMed 18848314); Kattah JC, et al. Stroke 2009;40:3504-10 (PubMed 19762709).
Acute angle-closure glaucoma (the London series of 38 people): Siriwardena D, et al. Age Ageing 1996;25:421-3. PubMed 9003875
Guidance: Australian and New Zealand Association of Neurologists, Choosing Wisely Australia recommendation on brain imaging for non-acute primary headache; healthdirect, Nausea, Vomiting, Migraine, Gastroenteritis, Dehydration, Meningitis, Concussion, Vertigo, Heatstroke and Hot weather; NSW Health, Carbon monoxide poisoning and Heat-related illness; Department of Health Victoria, carbon monoxide advisory; Pregnancy, Birth and Baby, Headaches during pregnancy, Pre-eclampsia and Morning sickness; Headache Australia, Migraine symptoms, Vestibular migraine, Cyclical vomiting syndrome and Abdominal migraine; Stroke Foundation, Signs of stroke; NHS, Feeling sick, Diarrhoea and vomiting, Migraine and Carbon monoxide poisoning.

Headaches That Make You Feel Sick?

Book a consultation with Dr Ron Granot — neurologist with a special interest in headache, Bondi Junction. Ask your GP for a referral, then get in touch.

Book a Consultation

Call Us02 9388 0615

LocationSuite 301, Bondi Junction

Emailreception@eastneurology.com.au

Last reviewed: 17 October 2026 by Dr Ron Granot, FRACP — Consultant Neurologist, East Neurology, Bondi Junction.