Nausea and Vomiting

Authored by , Reviewed by Dr Laurence Knott on | Certified by The Information Standard

Nausea is the feeling of wanting to be sick (vomit). Vomiting is when you are sick, or 'throw up'. The contents of your stomach rise up your food pipe (gullet, or oesophagus) and spill out of your mouth or nose. Nausea and vomiting are controlled by a combination of the vomiting centre in your brain, and areas within your gut.

Nausea and vomiting may be due to many different causes. Common causes include food poisoning, a tummy bug (viral infection), drinking a lot of alcohol, and being pregnant. You should get medical advice if you vomit repeatedly for more than 48 hours or feel unwell or weak. If you vomit blood or have unexplained problems like weight loss or difficulty swallowing, you should see your GP urgently. The most common causes are mentioned below.

Nausea is the feeling of wanting to be sick (vomit). Vomiting is the way the body gets rid of the stomach's contents. In most cases, the nausea and vomiting settle down within 48 hours. Nausea and vomiting are caused by reflexes in our guts and brain which act together. Nausea and vomiting may be due to irritation of the stomach lining - for example, by:

  • Alcohol.
  • Food poisoning.
  • A tummy bug (gastroenteritis).

Nausea and vomiting may also be caused by a direct effect on the vomiting centre of the brain. This explains the nausea and vomiting that often occur with:

  • Migraines.
  • The early stages of pregnancy.
  • Inner ear infections.
  • Motion (travel) sickness.
  • Some medication such as chemotherapy medicines.

Feeling sick (nausea) and being sick (vomiting) can affect all ages. They are very common symptoms with many possible causes. Some causes are more likely in different age groups - for more information see below.

Outbreaks of vomiting may be caused by viruses such as norovirus. This is a group of highly infectious viruses which cause nausea, then vomiting and watery poo (diarrhoea). The vast majority of people recover within 48 hours. Babies and very elderly people may become lacking in fluid in the body (dehydrated) and need to be hospitalised. This is the most common tummy bug in the UK, and occurs especially in winter.

Nausea and/or vomiting are common side-effects with some kinds of medicines. People being treated for cancer with chemotherapy may experience nausea and vomiting. It may also be a problem after medication used to put you to sleep for operations (anaesthetics).

Elderly people who start to vomit unexpectedly may have an underlying problem such as a urinary tract infection or pneumonia. Repeated vomiting can cause dehydration, especially among the very old and very young.

The doctor will want to know how long your feeling sick and being sick (nausea and vomiting) have lasted and whether you have any other symptoms. The doctor will particularly ask about symptoms which may suggest an underlying serious condition. These are known as 'red flags'. The sort of information your doctor will want to know includes the following:

  • Did it start suddenly or develop over time? Did anything trigger it? How long has it lasted?
  • When do you vomit? Is it worse when you move your head?
  • Do you feel feverish?
  • Are you coughing up blood or bile?
  • Do you feel ill? Do you have a high temperature (fever), weight loss or tummy (abdominal) pains? Do you have headaches?
  • How much alcohol do you drink?
  • When was your last period? Could you be pregnant?
  • Have you started any new medication recently?

This information will help the doctor to work out the cause of your nausea and/or vomiting. Your doctor will examine you. He or she will check your temperature, chest and abdomen. You may be asked to produce a urine sample and have a blood test. You may be asked to do a pregnancy test. Further tests of your stomach and abdomen may be advised. Referral to a specialist is possible.

The following features may indicate serious underlying disease:

There are many causes of feeling sick and being sick (nausea and vomiting). Some of the more common ones are discussed briefly below. There may be a link to a leaflet with more information for many of the causes listed.


Gastroenteritis is an infection of the gut. It causes runny poo (diarrhoea) and may also cause vomiting, tummy (abdominal) pain and other symptoms. In most cases the infection clears within a few days but sometimes it takes longer. The diarrhoea and vomiting are your body's way of getting rid of the germs. Usually no treatment is needed. The main risk is loss of water from the body (dehydration). The most important thing is to have plenty to drink, or give your child lots to drink. This may mean giving special rehydration drinks. Also, once any dehydration is treated with drinks, you or your child should eat as normally as possible. See separate leaflets called Gastroenteritis in Children and Gastroenteritis in Adults for more information.

Some cases of gastroenteritis are caused by eating infected food, or drinking contaminated water. See the separate leaflets called Food Poisoning in Children and Food Poisoning in Adults for more information.

Urine Infection

Urine infection in children is common. It can cause various symptoms, including vomiting. A course of antibiotics will usually clear the infection quickly. In most cases, a child with a urine infection will make a full recovery. Sometimes tests to check on the kidneys and/or bladder are advised after the infection has cleared. Your doctor will advise if your child needs these tests. This depends on your child's age, the severity of the infection and whether it has happened before. See separate leaflet called Urine Infection in Children for more details.

Urine infections and kidney infections are also common in adults. Sometimes nausea or vomiting can be the first symptom. There may be associated symptoms such as:

  • Burning sensation on passing urine.
  • Needing to pass urine more often.
  • Back pain or low tummy pain.
  • A high temperature (fever).

In older adults, the symptoms of urine infections can be more vague. Often confusion is the first symptom. See the separate leaflets called Urine infection in Older People, and Kidney Infection (Pyelonephritis) for more details.


Many women have nausea and vomiting during the first 12 weeks of pregnancy. In most cases it is mild and does not need any specific treatment. In more severe cases, an anti-sickness medicine is sometimes used. Examples include promethazine and prochlorperazine. A rare form of extreme vomiting in pregnancy (hyperemesis gravidarum) can result in dehydration and even require a short hospital stay. See separate leaflet called Morning Sickness in Pregnancy for more details.


Migraine causes attacks of headaches, often with feeling sick or vomiting. Treatment options include:

See separate leaflet called Migraine for more details.


Labyrinthitis and vestibular neuritis are most commonly caused by a viral infection that affects the inner ear. These conditions typically cause intense dizziness, often with vomiting (vertigo). In most cases the symptoms gradually ease and go within a few weeks as the infection clears. Medication may help to ease symptoms. There are some less common causes which may have a different outlook and treatment. See separate leaflet called Labyrinthitis and Vestibular Neuritis for more detail.

Motion (travel) sickness

The inner ear is also responsible for motion sickness. Motion sickness is caused by disturbance of the inner ear which controls balance. Many people develop nausea and vomiting on a boat or long car ride. There are medicines which can help - for example, hyoscine or Stugeron®. See separate leaflet called Motion (Travel) Sickness for more information.


Many medicines can cause nausea and vomiting. Chemotherapy medicines used to treat cancer often cause nausea and vomiting. They tend to cause less nausea and vomiting than in the past and the symptoms can usually be well controlled with other medication. Opioid medicines such as morphine commonly cause nausea and vomiting. Many other medicines can cause nausea and vomiting - for example, anaesthetics and antibiotics. Be sure to mention any new medication or dietary changes to your doctor who may be able to suggest substitutes.

Other causes

Appendicitis, inflammation of the pancreas (pancreatitis), kidney stones, stomach ulcers and gallstones can all cause severe tummy (abdominal) pain and nausea and vomiting. If severe, ring 999/112/911 to call for an ambulance.

Blockage (obstruction) - repeated and severe vomiting may be due to a blockage anywhere along the gut (intestine). This could be a twisted loop of bowel, cancerous growth or non-cancerous narrowing. This will usually be associated with severe tummy pain. Because there is a blockage, usually you would be unable to open your bowels. This is an emergency and you need to call an ambulance.

Raised pressure in the brain - meningitis, brain tumours and head injuries can increase pressure in the brain, which can cause nausea and vomiting. Ring 999/112/911 to call for an ambulance if you suspect your child has meningitis.

Kidney problems or liver problems may cause nausea and vomiting as your body is unable to get rid of toxins and poisons as well as usual. Uncontrolled diabetes can cause nausea and vomiting. A blood test should help to diagnose these less common causes.

Eating disorders - some people make themselves vomit as part of an eating disorder (bulimia nervosa).

Treatment will depend on the likely cause of your feeling sick and being sick (nausea and vomiting). In many cases (for example, caused by tummy bugs) you will not need any treatment. The nausea and vomiting stop when your body has rid itself of the infection.

You will be strongly encouraged to cut down alcohol if you drink more than the recommended amount.

You will be offered advice if you are pregnant but medication is usually not needed unless you are lacking in fluid in your body (dehydrated).

You may be referred to a specialist for further tests. Most cases will be managed by your doctor but you may be referred for further investigation and treatment at a hospital.

  • Avoid a lack of fluid in your body (dehydration): drink little and often to replace any fluid you have lost. Consider using rehydration drinks, such as Dioralyte┬«.
  • Call 999/112/911 if being sick (vomiting) is severe and you are weak or have severe tummy (abdominal) pain.
  • See your doctor urgently (within a few days) if you develop 'red flag' symptoms.
  • See your doctor if your vomiting lasts for more than 48 hours and is not improving.

Careful hand washing and hygiene help to prevent the spread of tummy (abdominal) bugs. Thorough cooking and food hygiene minimise the risk of food poisoning. Avoid excessive alcohol and get help if you are dependent on alcohol. People who have migraines may be able to identify triggers that they can try to avoid - for example, foods like cheese.

This depends on the underlying cause but is generally very good. Most feeling sick and being sick (nausea and vomiting) are due to short-lived viral infections, do not need special treatment and should get better within a week.

Further reading and references

  • ; NICE CKS, June 2013 (UK access only)

  • ; NICE CKS, July 2015 (UK access only)

  • ; NICE Clinical Guideline (April 2009)

  • ; Public Health England (March 2012)

  • ; Interventions for nausea and vomiting in early pregnancy. Cochrane Database Syst Rev. 2015 Sep 89:CD007575.

  • ; NICE CKS, July 2015 (UK access only)

  • ; Scopolamine (hyoscine) for preventing and treating motion sickness. Cochrane Database Syst Rev. 2011 Jun 15(6):CD002851.

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