Headache and Nausea: 13 Critical Causes and Safe Relief

Your head hurts and your stomach feels unsettled at the same time. That combination can make even a simple day feel difficult.

Most cases are not caused by a dangerous illness, but the pattern matters.

Quick answer: Headache and nausea commonly occur together with migraine, dehydration, viral illness, food poisoning, missed meals, low blood sugar, medicine effects, motion sickness, pregnancy, or stress. Migraine becomes more likely when nausea appears with throbbing head pain and sensitivity to light or sound. Sudden severe headache, neurological symptoms, stiff neck, seizure, serious head injury, or sudden vision loss needs urgent assessment.

Do not judge the cause from nausea alone. Look at how the headache started, where it hurts, what else you feel, and whether this episode is different from your usual headaches.

This article is for general information and education. It does not replace medical advice, diagnosis, or treatment.

Why Do Headache and Nausea Happen Together?

The brain, balance system, digestive tract, nerves, hormones, and blood vessels all communicate with one another.

This is why a problem that starts in the nervous system can make your stomach feel sick, and why an illness that causes vomiting or dehydration can later produce a headache.

Migraine is one of the clearest examples.

A migraine is more than head pain. It is a neurological disorder that can cause:

• Throbbing headache
• Nausea
• Vomiting
• Light sensitivity
• Sound sensitivity
• Dizziness
• Visual or sensory aura in some people

For a detailed comparison, read Migraine vs Headache: 9 Warning Signs You Should Know.

13 Important Causes of Headache and Nausea

1. Migraine

Migraine is one of the most common reasons headache and nausea occur together.

The pain may be moderate or severe and can feel throbbing or pulsating. It is often stronger on one side, but migraine can also affect both sides.

Other clues include:

• Light sensitivity
• Sound sensitivity
• Vomiting
• Worsening with normal activity
• A need to rest in a quiet room

Some people have aura before or during the attack. Others never have aura.

Do not diagnose every one sided headache as migraine, especially when the headache is completely new or has unusual neurological symptoms.

2. Dehydration

Dehydration can produce headache, weakness, dizziness, thirst, and nausea.

It can happen after:

• Vomiting
• Diarrhea
• Heavy sweating
• Hot weather
• Fever
• Not drinking enough

Look for clues such as dark urine, urinating less than usual, dry mouth, or feeling lightheaded when standing.

Do not use a fixed “eight glasses” rule for everyone. Fluid needs vary with body size, weather, activity, health conditions, and fluid losses.

3. Viral Infection

Cold, flu, COVID, and other viral illnesses can cause headache and nausea.

You may also have:

• Fever
• Body aches
• Cough
• Sore throat
• Fatigue
• Diarrhea
• Vomiting

A headache during an infection can also become worse if you are dehydrated or eating very little.

See COVID Headache: 9 Crucial Clues and Safer Relief when COVID is part of the concern.

4. Food Poisoning or Gastroenteritis

Viral gastroenteritis and food poisoning can cause nausea, vomiting, abdominal cramps, and diarrhea.

The headache may come from the infection itself, fever, dehydration, or reduced food intake.

The priority is usually replacing fluid and watching for signs of dehydration.

Seek care if you cannot keep liquids down, become faint, have blood in vomit or stool, or develop severe abdominal pain.

5. Missed Meals or Low Blood Sugar

Skipping meals can trigger headache in some people.

True low blood sugar can also cause:

• Sweating
• Shaking
• Weakness
• Dizziness
• Confusion
• Nausea
• Headache

This matters especially if you use insulin or medicine that lowers blood glucose.

Severe confusion, seizure, or unconsciousness with suspected low glucose is an emergency.

People without diabetes can also experience hypoglycemia for less common reasons. Read What Causes Low Blood Sugar Without Diabetes?.

6. Medication Side Effects or Withdrawal

Medication side effects can cause both symptoms.

Possible culprits vary widely and can include some:

• Antibiotics
• Pain medicines
• Antidepressants
• Hormonal medicines
• Blood pressure medicines
• Cancer treatments

Stopping certain medicines suddenly can also cause headache and nausea.

Do not stop a prescription because you suspect a side effect. Ask the prescriber or pharmacist first.

7. Alcohol, Caffeine, or Nicotine

Too much alcohol can cause headache, nausea, thirst, and dizziness.

Caffeine can create a different problem. A person who normally drinks caffeine every day can develop headache when they suddenly stop.

High doses of nicotine can also cause headache, nausea, dizziness, and a fast heartbeat.

The useful question is not whether these substances are always bad. It is whether your symptom pattern repeatedly follows use, excess use, or withdrawal.

8. Motion Sickness or a Balance Disorder

Motion sickness happens when signals from your eyes, inner ears, and body movement do not match.

Nausea is usually prominent.

You may also have:

• Dizziness
• Sweating
• Paleness
• Vomiting
• Head discomfort

Inner ear problems can also cause dizziness and nausea, sometimes with headache.

If dizziness is the main symptom, read How to Stop Feeling Dizzy.

9. Pregnancy and Hormonal Changes

Early pregnancy commonly causes nausea.

Headaches can also occur because of hormonal changes, sleep changes, stress, reduced food intake, or caffeine withdrawal.

Later pregnancy needs more caution.

A headache that will not go away, especially with vision changes, swelling of the face or hands, upper abdominal pain, breathing difficulty, or nausea and vomiting in the second half of pregnancy, can be a sign of preeclampsia.

That requires prompt obstetric assessment.

Pregnancy medicine safety also differs from usual headache care, so do not assume ibuprofen, naproxen, migraine medicine, or anti nausea medicine is safe without checking.

Visit the Women's Health Hub for related pregnancy and postpartum guides.

10. Stress and Anxiety

Stress can contribute to tension headache or trigger migraine in susceptible people.

Anxiety can also cause nausea, dizziness, rapid breathing, stomach discomfort, and a racing heartbeat.

This does not mean a severe new headache should be blamed on anxiety before important causes are considered.

If stress is a repeated trigger, regular sleep, meals, exercise, relaxation, and mental health support can help the wider pattern.

11. Head Injury or Concussion

A concussion can cause:

• Headache
• Nausea
• Dizziness
• Balance problems
• Memory trouble
• Light sensitivity
• Vomiting

A worsening headache, repeated vomiting, seizure, unusual behavior, confusion, weakness, or loss of consciousness after a head injury needs urgent medical assessment.

Do not use pain relief to hide worsening neurological symptoms after significant trauma.

12. Severe High Blood Pressure or Preeclampsia

Most people with routine high blood pressure have no symptoms.

Headache and nausea should not be used to diagnose hypertension.

However, dangerously high blood pressure with organ symptoms can be an emergency.

Pregnancy deserves special attention because preeclampsia can cause a persistent severe headache, vision changes, upper abdominal pain, nausea, vomiting, and breathing problems.

A pregnant or recently postpartum person with these symptoms should contact obstetric care urgently.

13. A Serious Brain or Nervous System Problem

Rarely, headache with nausea is caused by a dangerous neurological condition.

Examples include:

• Stroke
• Bleeding around the brain
• Meningitis
• Encephalitis
• Raised pressure inside the skull

The warning signs matter more than trying to decide which rare condition is present at home.

Sudden severe headache, weakness, speech trouble, confusion, seizure, vision loss, stiff neck, or high fever needs urgent medical assessment.

One Often Missed Cause: Carbon Monoxide

Carbon monoxide exposure can cause headache, nausea, dizziness, weakness, and confusion.

Think about it when several people in the same house, workplace, vehicle, or enclosed space become ill at about the same time.

Symptoms may improve when you leave the building and return when you go back inside.

If carbon monoxide exposure is possible, leave the area, move into fresh air, and contact emergency services. Do not remain inside trying to identify the appliance yourself.

How Can You Tell Migraine From a Regular Headache?

Migraine does not always follow the textbook pattern. It can affect both sides, and some attacks cause more nausea than head pain.

What Can You Do at Home for Mild Headache and Nausea?

Self care makes sense when symptoms are mild, familiar, and there are no warning signs.

Rest Somewhere Quiet

If light or sound makes the headache worse, a dim and quiet room can be more comfortable.

Take Small Sips of Fluid

If you feel nauseated, large drinks can be hard to tolerate.

Take small, frequent sips instead.

If vomiting or diarrhea has caused major fluid loss, an oral rehydration drink may be useful.

Eat When You Can

An empty stomach can make some people feel worse.

Try small portions of foods that you tolerate.

There is no single “headache diet” that works for everyone.

Reduce Strong Sensory Triggers

Bright light, loud noise, strong odors, and intense screen use can make migraine symptoms harder to tolerate.

Reduce these exposures during an attack if they bother you.

Do Not Force Exercise During Severe Symptoms

Regular exercise can support long term health and migraine prevention for some people.

That is different from exercising through active vomiting, significant dizziness, or a severe migraine.

Which Medicines Can Help?

Treatment depends on the cause.

A medicine that helps migraine may be useless for food poisoning, and an anti nausea medicine does not treat meningitis or stroke.

Simple Pain Relief

Acetaminophen, also called paracetamol, or an anti inflammatory medicine such as ibuprofen may help some headache types.

They are not safe for everyone.

NSAIDs such as ibuprofen can be unsuitable for people with:

• Stomach ulcers
• Kidney disease
• Some heart conditions
• Some bleeding risks
• Certain stages of pregnancy

Use the package directions and ask a pharmacist or clinician when you are unsure.

Migraine Specific Treatment

If migraine is diagnosed, treatment can include medicines designed specifically for migraine.

Options can include:

• Triptans
• Gepants
• Selected nasal treatments
• Anti nausea medicines

Which one is suitable depends on your cardiovascular health, other medicines, pregnancy status, and how often attacks happen.

Anti Nausea Medicine

Doctors sometimes use medicines such as metoclopramide or prochlorperazine during migraine attacks with nausea or vomiting.

These medicines have their own risks and are not suitable for every person.

Do not use someone else's prescription.

Why Opioids and Butalbital Are Poor Routine Choices

The older version of this article listed opioid and butalbital products as treatment options for severe headaches.

That deserves correction.

Modern migraine treatment usually avoids opioids and barbiturate products because better options exist and these medicines can cause dependence and medication overuse headache.

If you already use one regularly, do not stop a dependence forming medicine suddenly without professional advice.

Can Taking Too Much Headache Medicine Make Headaches Worse?

Yes.

Frequent use of acute headache medicine can create a cycle called medication overuse headache.

The person takes medicine because of headaches, then the medicine itself contributes to more frequent headaches.

This can happen with several types of acute headache treatment.

If you need pain medicine on many days each month, discuss your pattern with a doctor rather than simply increasing the dose.

A preventive migraine treatment may be more appropriate.

What if You Are Pregnant?

Pregnancy changes both the causes of headache and which medicines are safe.

ACOG advises discussing headache medicines with your obstetric clinician.

Acetaminophen is commonly used when appropriate during pregnancy.

Ibuprofen and naproxen should not be taken during pregnancy unless specifically recommended by your obstetric professional, and their safety depends on pregnancy stage.

Most importantly, seek prompt obstetric advice for a headache that will not go away, especially later in pregnancy or after childbirth when it appears with:

• Vision changes
• Swelling of the face or hands
• Upper abdominal or shoulder pain
• Nausea or vomiting
• Breathing difficulty

These can be warning signs of preeclampsia.

When Does Vomiting Become More Concerning?

Do not wait for a fixed number of hours if you are getting sicker.

Seek prompt medical care when vomiting causes signs of dehydration such as:

• Very little urine
• Dark urine
• Severe thirst
• Dry mouth
• Weakness
• Dizziness or faintness when standing

Urgent assessment is also needed when vomit:

• Contains blood
• Looks like coffee grounds
• Is green

Severe headache with new vomiting also deserves more attention when that headache is different from your usual pattern.

What About Headache, Nausea, and Dizziness Together?

This combination can occur with:

• Migraine
• Dehydration
• Motion sickness
• Inner ear disorders
• Low blood glucose
• Viral illness
• Some medicines

Sudden dizziness with weakness, speech problems, severe imbalance, or vision loss can also signal stroke.

See Dizzy Spells in the Morning if dizziness is a recurring part of your symptom pattern.

Can Allergies Cause Headache and Nausea?

Allergy and nasal symptoms can contribute to facial pressure or headache.

But repeated severe headache with nausea, light sensitivity, and sound sensitivity is often more suggestive of migraine than a simple allergy headache.

The distinction matters because treatment is different.

See Allergies That Cause Headaches.

Can Hemiplegic Migraine Cause Nausea?

Yes.

Hemiplegic migraine can include migraine headache, nausea, aura, and temporary weakness.

However, new one sided weakness should never be assumed to be migraine at home because stroke can look similar.

Emergency assessment is appropriate for first time or unusual weakness.

Read Living With Hemiplegic Migraine for a detailed guide.

Do You Need a Brain Scan?

Not every headache with nausea needs CT or MRI.

Most routine headaches are diagnosed from:

• Your symptom history
• Neurological examination
• Headache pattern
• Medical history
• Medication use

Imaging becomes more important when symptoms suggest a secondary cause.

Examples include:

• Sudden thunderclap headache
• New neurological loss
• Seizure
• Head injury
• Abnormal neurological examination
• Another serious cause suspected by the clinician

A colonoscopy, EEG, ultrasound, CT scan, or MRI should not be presented as routine tests for every person with headache and nausea.

How to Keep a Useful Headache and Nausea Diary

A short symptom record can reveal patterns that memory misses.

When Should You Book a Routine Medical Appointment?

Arrange an appointment if:

• Headaches are happening more often
• They are becoming more severe
• The pattern has changed
• Nausea repeatedly comes with the headaches
• You regularly vomit during headaches
• The headaches interrupt work, sleep, school, or daily life
• You need acute pain medicine frequently
• Current treatment no longer helps

A diagnosis can open the door to better treatment, especially when recurrent migraine is the cause.

Common Headache and Nausea Mistakes

Assuming Every Episode Is Migraine

A familiar migraine pattern is useful. A first or very different severe headache still needs proper assessment.

Calling Every Headache a Sinus Headache

Migraine can cause facial pressure, nasal symptoms, and nausea too.

Forcing Huge Amounts of Water

Replace normal fluid losses, but more water is not always better and can be unsafe in some medical conditions.

Skipping Meals Because You Feel Sick

Small tolerated meals can help when an empty stomach or low glucose is contributing.

Taking More Pain Medicine Every Time the Headache Returns

Frequent acute medicine can contribute to medication overuse headache.

Using Opioids as a Routine Migraine Treatment

More specific and safer treatment options usually exist.

Ignoring Pregnancy Warning Signs

Persistent headache and visual symptoms later in pregnancy need prompt assessment for preeclampsia.

Ignoring a Sudden New Pattern

A sudden severe headache is not the time to test a new home remedy.

Conclusion

Headache and nausea can come from something as common as migraine, dehydration, a viral illness, or a missed meal. They can also occur with pregnancy, medicine effects, concussion, or a serious neurological illness.

The safest approach is to look at the whole pattern. Ask how fast the headache started, whether it feels like your normal headaches, whether you can keep fluids down, and whether weakness, vision changes, fever, confusion, or neck stiffness are present.

Your next step is simple: for mild familiar symptoms, rest, hydrate sensibly, eat small tolerated meals, and use medicines safely. If the headache is sudden, severe, unusual, or accompanied by neurological warning signs, seek medical care instead of waiting for it to pass.

References and Sources

1. NHS. Headaches.Guidance on common headache causes, symptom diaries, urgent warning signs, neurological symptoms, vomiting, fever, stiff neck, head injury, and when emergency assessment is needed.https://www.nhs.uk/symptoms/headaches/
2. Mayo Clinic. Migraine Diagnosis and Treatment.Current guidance on migraine treatment, triptans, gepants, anti nausea medicines, preventive treatments, medication overuse, and why opioids are usually avoided.https://www.mayoclinic.org/diseases-conditions/migraine-headache/diagnosis-treatment/drc-20360207
3. Mayo Clinic. Nausea and Vomiting.Updated 2026 guidance on common causes of nausea and vomiting, dehydration, migraine, pregnancy, medicines, and emergency warning signs.https://www.mayoclinic.org/symptoms/nausea/basics/causes/sym-20050736
4. Centers for Disease Control and Prevention. Signs and Symptoms of Stroke.2026 guidance on sudden weakness, numbness, speech problems, vision problems, balance loss, and sudden severe headache as stroke warning signs.https://www.cdc.gov/stroke/signs-symptoms/
5. NHS. Meningitis.Current guidance on severe headache, vomiting, fever, stiff neck, confusion, light sensitivity, seizure, rash, and emergency care.https://www.nhs.uk/conditions/meningitis/
6. American College of Obstetricians and Gynecologists. Headaches and Pregnancy.Guidance on headache treatment in pregnancy and warning signs of preeclampsia, including persistent headache, vision changes, upper abdominal pain, and nausea or vomiting.https://www.acog.org/womens-health/faqs/headaches-and-pregnancy

Internal Links + Hub

• Pain Management and Conditions Hub
• Migraine vs Headache
• Types of Headaches and Location
• COVID Headache
• Living With Hemiplegic Migraine
• Allergies That Cause Headaches
• How to Stop Feeling Dizzy
• Dizzy Spells in the Morning
• What Causes Low Blood Sugar Without Diabetes?
• Women's Health Hub
• Infections and Immune Health Hub

Frequently Asked Questions About Headache and Nausea

What is the most common cause of headache and nausea together?

Migraine is one of the most common causes. Migraine often produces moderate or severe throbbing pain along with nausea, vomiting, and sensitivity to light or sound.

Can dehydration cause headache and nausea?

Yes. Dehydration can cause headache, nausea, weakness, thirst, dark urine, and dizziness. It commonly follows vomiting, diarrhea, fever, heavy sweating, or inadequate fluid intake.

Can low blood sugar cause headache and nausea?

Yes. Low blood glucose can cause headache and nausea together with sweating, shaking, weakness, dizziness, and confusion. People using insulin or glucose lowering medicines need particular caution.

Can stress cause headache and nausea?

Yes. Stress can trigger migraine or tension headache in some people and can also produce nausea and other stomach symptoms. A severe new headache should not automatically be blamed on stress.

Can pregnancy cause headache and nausea?

Yes. Nausea is common in early pregnancy and headaches can also occur. Later in pregnancy, a persistent headache with vision changes, upper abdominal pain, swelling, or nausea and vomiting can indicate preeclampsia and needs prompt medical assessment.

What helps migraine nausea?

Resting in a quiet dark room, taking small sips of fluid, and using prescribed or appropriate migraine treatment can help. Doctors may use specific anti nausea medicines when nausea or vomiting is significant.

Can taking too many painkillers cause headaches?

Yes. Frequent use of acute headache medicines can contribute to medication overuse headache. If you need headache medicine very often, discuss preventive treatment and medicine use with a healthcare professional.

Should I take ibuprofen for headache and nausea?

Ibuprofen can help some headache types, but it is not suitable for everyone. Kidney disease, ulcers, bleeding risk, heart conditions, other medicines, and pregnancy can change whether it is safe.

Why do I have headache, nausea, and dizziness together?

Possible causes include migraine, dehydration, motion sickness, inner ear problems, viral illness, low blood glucose, or medicine effects. Sudden dizziness with weakness, speech trouble, severe imbalance, or vision loss requires urgent assessment.

Can carbon monoxide cause headache and nausea?

Yes. Carbon monoxide can cause headache, nausea, dizziness, weakness, and confusion. Suspect it if several people in the same enclosed place become ill. Leave the area and seek emergency help.

When is headache and nausea an emergency?

Seek emergency help for a sudden extremely severe headache, weakness or numbness, speech trouble, vision loss, confusion, seizure, fainting, high fever with a stiff neck, serious head injury, or another major neurological change.

Do I need a brain scan for headache and nausea?

Not usually for a familiar uncomplicated headache pattern. Imaging is more likely when the headache is sudden or unusual, neurological symptoms are present, examination findings are abnormal, significant head injury occurred, or another serious cause is suspected.