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Gastroenteritis is inflammation of your stomach or bowels, usually caused by an infection, and can lead to symptoms such as diarrhoea, feeling sick, vomiting and pain in your abdomen (tummy).

About gastroenteritis

In the UK, about one in five people get an infection causing gastroenteritis each year. It's more common in babies and young children who may have it more than once a year. If you have gastroenteritis, it generally goes without you needing medical treatment. If a baby or a young child has gastroenteritis, it can be more dangerous because he or she becomes dehydrated more easily.

Your stomach and bowels are known as your gastrointestinal tract or gut. Gastroenteritis is an infection of your gut. You can get an infection by eating or drinking food that is contaminated with bacteria, viruses or parasites, or from other people with an infection. Bacteria, viruses and parasites can damage the cells lining the inner surface of your gut and stop it working as it should.

Certain bacteria or viruses may also produce poisons called toxins that can irritate your gut and cause it to produce excess fluid. This can cause the symptoms of gastroenteritis, such as diarrhoea.

Symptoms of gastroenteritis

The time between catching the infection and the start of symptoms (the incubation period) depends on the type of infection you have. It can range from one hour to a few weeks but it's usually between one and three days.

You may have symptoms including:

  • diarrhoea, which may contain blood and mucus, or be watery, greasy or frothy
  • feeling sick or vomiting
  • abdominal cramps, bloating, stomach rumbling or pain
  • loss of appetite
  • a fever

The time it takes to recover depends on what infection you have. Most people recover fully within approximately 10 days, although you’re likely to start feeling better sooner than that. However, severe infections, which are uncommon in the UK, may last for many weeks. It's important to go to your GP if your symptoms last for more than a week, or if you have recently travelled abroad.

For children with gastroenteritis, diarrhoea usually lasts for five to seven days and stops within two weeks, and vomiting usually lasts for one to two days, stopping within three days. If the symptoms continue for longer than this, see your GP.

In adults and older children, the symptoms of gastroenteritis may be confused with other conditions, such as ulcerative colitis.

Complications of gastroenteritis

Complications from gastroenteritis occur mainly in young children or in adults who are over the age of 65, people who have other long-term medical conditions or those who have a weakened immune system.

Possible complications of gastroenteritis include:

Contact your GP if you:

  • have severe pain or pain that doesn't respond to over-the-counter painkillers
  • have vomiting or diarrhoea that continues for more than a few days, or you can't drink or eat without being sick – this is particularly important if you can’t keep down fluids
  • have blood or mucus in your diarrhoea
  • have signs of dehydration, including a very dry mouth, muscle cramps, reduced urine, sunken eyes and, later, confusion or irritability
  • have recently travelled abroad
  • can't take medicines you usually take for other conditions without being sick

Causes of gastroenteritis

The main causes of gastroenteritis are infection with a virus, bacteria or parasite.


Viruses are a main cause of gastroenteritis, particularly in children. These include:

  • rotavirus – this is the most common cause of severe symptoms in children
  • norovirus – this is very contagious but the symptoms are usually mild
  • adenovirus – this most commonly affects young children

Viral infections can be seasonal. There is a peak of rotavirus and norovirus infections during the winter months.


The most common cause of bacterial gastroenteritis is food poisoning. Different bacteria that cause food poisoning include Salmonella, Campylobacter and Escherichia coli (E. coli).


Parasites rarely cause gastroenteritis in the UK, but they are a major problem in less developed countries and you may get infected when abroad. Giardia is a common parasite that is found in water, soil and food.

How is gastroenteritis spread?

You can become infected with gastroenteritis in different ways. These include:

  • in contaminated food, for example, when it’s not cooked thoroughly or is unpasteurised – see our frequently asked questions for more information
  • from person to person – this happens if an infected person goes to the toilet and doesn't wash his or her hands properly afterwards, before handling food or touching other people
  • contaminated items such as door handles and work surfaces
  • in shellfish harvested from polluted waters
  • in contaminated drinking water – in less developed countries this is how the majority of infections occur
  • contact with a contaminated animal

Diagnosis of gastroenteritis

Your GP will ask about your symptoms and examine you. He or she will ask how often you have vomited, about the frequency and consistency of your bowel movements, how much urine you’re passing, whether you have any blood in your faeces and if you have been able to keep down any food or drink.

Your GP may also ask about your medical history or if you have been in recent contact with someone who had diarrhoea or vomiting. He or she may also ask you whether you work with food or if you have eaten anything – either at home or in a restaurant – that might have been contaminated.

It's important to tell your GP if you have been travelling, including which countries you have visited and any vaccinations you had. Your GP may ask you for a sample of faeces to send for laboratory testing.

Treatment of gastroenteritis


If you have gastroenteritis, you’re likely to be infectious to others. Stay at home and don’t go into work for at least 48 hours or until your symptoms get better. Keep your children off school until their symptoms have gone.

The most important thing to do is replace the fluids and salts you have lost to prevent dehydration. If you have mild gastroenteritis, drinks such as water and squash will help to keep you hydrated – don’t have fizzy or caffeinated drinks, or fruit juice until you have recovered. If you feel well enough, you can have small, light meals but don't have fatty or spicy foods.

If you have a more severe infection, use an oral rehydration solution (eg Dioralyte). This is a powder that is made up into a solution by adding water. It contains the right balance of sugars and salts for your body to encourage rehydration. You may find it better to stick to plain foods such as rice or toast until you feel that you can eat as usual. See our frequently asked questions for more information.

Certain probiotics (foods containing ‘good’ bacteria that occur naturally in your body) can help to reduce the duration of diarrhoea. However, not all types are effective at improving symptoms and it will also depend on what caused your gastroenteritis. See our frequently asked questions for more information.

If your baby has gastroenteritis and you're breastfeeding, continue to breastfeed if possible – see your GP if your baby can’t breastfeed. Don’t give your child anything to eat until he or she can drink enough and is fully rehydrated.


If gastroenteritis is causing you pain, take an over-the-counter painkiller, such as paracetamol or ibuprofen.

Medicines to stop diarrhoea such as loperamide (eg Imodium) are only recommended for adults and children over four years old. These medications slow down the action of your bowels so the contents take longer to pass through. Diarrhoea is only prevented temporarily while you’re taking these medicines but they are useful, for example, if you need to travel and won't be near a toilet. Don’t take these medicines if you have blood or mucus in your faeces or you have a high fever.

Your GP may prescribe you a medicine to help you stop being sick called an anti-emetic. Antiemetics can be helpful if you have severe vomiting.

Gastroenteritis caused by viruses can't be treated with antibiotics so your GP won't usually prescribe them. However, if your GP suspects that you have a bacterial infection, he or she may ask you for a faeces sample to send for laboratory testing, particularly if you have been travelling recently, work with food or could have developed food poisoning. The results will help to determine if you can be treated with antibiotics.

Always read the patient information that comes with your medicine and if you have any questions, ask your pharmacist for advice.

Hospital treatment

If you have lost so much fluid that you're very dehydrated, you may need to be admitted to hospital so that fluids can be replaced directly into your bloodstream via a catheter into your vein (intravenously).

Prevention of gastroenteritis

The best way to reduce your risk of catching gastroenteritis is to always wash your hands with soap and water after going to the toilet. Make sure you also always wash your hands before and after preparing or eating food.

Make sure you have any necessary vaccinations before you travel to other countries and drink bottled water where necessary when you’re abroad. Don’t have ice in drinks unless you’re sure that the water is safe to drink.

If you have gastroenteritis, you can help to prevent spreading the infection to others.

  • Hygienically dispose of, or properly clean, all soiled items such as towels or dirty nappies if your baby is ill.
  • Wash soiled clothing or bed linen away from other laundry and at the highest temperature available (60°C or higher if possible). Only half fill the washing machine so that everything can be thoroughly cleaned and rinsed.
  • Clean the toilet with disinfectant.
  • Wipe toilet seats, flush handles, taps, surfaces and toilet door handles daily with hot water and disinfectant. Use a cloth that can be thrown away or one that is only used for this purpose.
  • Don't share towels and flannels.
  • Don't prepare food for others.
  • Don’t go swimming for at least two weeks after your diarrhoea has stopped.


Produced by Polly Kerr, Bupa Health Information Team, November 2012.

For answers to frequently asked questions on this topic, see FAQs.

For sources and links to further information, see Resources.

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  • This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.

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