Gastroenteritis is a very common condition that causes diarrhoea and vomiting. It's usually caused by a bacterial or viral tummy bug.

It affects people of all ages, but is particularly common in young children.

Most cases in children are caused by a virus called rotavirus. Cases in adults are usually caused by norovirus (the "winter vomiting bug") or bacterial food poisoning.

Gastroenteritis can be very unpleasant, but it usually clears up by itself within a week. You can normally look after yourself or your child at home until you're feeling better.

Try to avoid going to your GP, as gastroenteritis can spread to others very easily. Call NHS 111 or your GP if you're concerned or need any advice.

This page covers:

Symptoms

What to do if you have it

When to get medical advice

Looking after a child

Getting medical advice for your child

How it's spread

Prevention

Symptoms of gastroenteritis

The main symptoms of gastroenteritis are:

• sudden, watery diarrhoea
• feeling sick
• vomiting, which can be projectile
• a mild fever

Some people also have other symptoms, such as a loss of appetite, an upset stomach, aching limbs and headaches.

The symptoms usually appear up to a day after becoming infected. They typically last less than a week, but can sometimes last longer.

What to do if you have gastroenteritis

If you experience sudden diarrhoea and vomiting, the best thing to do is stay at home until you're feeling better. There's not always a specific treatment, so you have to let the illness run its course.

You don't usually need to get medical advice, unless your symptoms don't improve or there's a risk of a more serious problem (see When to get medical advice).

To help ease your symptoms:

• Drink plenty of fluids to avoid dehydration – You need to drink more than usual to replace the fluids lost from vomiting and diarrhoea. Water is best, but you could also try fruit juice and soup.
• Take paracetamol for any fever or aches and pains.
• Get plenty of rest.
• If you feel like eating, try small amounts of plain foods, such as soup, rice, pasta and bread.
• Use special rehydration drinks made from sachets bought from pharmacies if you have signs of dehydration, such as a dry mouth or dark urine – read about treating dehydration.
• Take anti-vomiting medication (such as metoclopramide) and/or antidiarrhoeal medication (such as loperamide) if you need to – some types are available from pharmacies, but check the leaflet that comes with the medicine. You can also ask your pharmacist or GP for advice about whether they're suitable. 

Gastroenteritis can spread very easily, so you should wash your hands regularly while you're ill and stay off work or school until at least 48 hours after your symptoms have cleared, to reduce the risk of passing it on (see Preventing gastroenteritis).

When to get medical advice

You don't normally need to see your GP if you think you have gastroenteritis, as it should get better on its own.

Visiting your GP surgery can put others at risk, so it's best to call NHS 111 or your GP if you're concerned or feel you need advice.

Get medical advice if:

• you have symptoms of severe dehydration, such as persistent dizziness, only passing small amounts of urine or no urine at all, or if you're losing consciousness
• you have bloody diarrhoea
• you're vomiting constantly and are unable to keep down any fluids
• you have a fever over 38C (100.4F)
• your symptoms haven't started to improve after a few days
• in the last few weeks you've returned from a part of the world with poor sanitation
• you have a serious underlying condition, such as kidney disease, inflammatory bowel disease or a weak immune system, and have diarrhoea and vomiting

Your GP may suggest sending off a sample of your poo to a laboratory to check what's causing your symptoms. Antibiotics may be prescribed if this shows you have a bacterial infection.

Looking after a child with gastroenteritis

You can look after your child at home if they have diarrhoea and vomiting. There's not usually any specific treatment and your child should start feeling better in a few days.

You don't normally need to get medical advice unless their symptoms don't improve or there's a risk of a more serious problem (see Getting medical advice for your child).

To help ease your child's symptoms:

• Encourage them to drink plenty of fluids. They need to replace the fluids lost from vomiting and diarrhoea. Water is generally best. Avoid giving them fizzy drinks or fruit juice, as they can make their diarrhoea worse. Babies should continue to feed as usual, either with breast milk or other milk feeds.
• Make sure they get plenty of rest.
• Let your child eat if they're eating solids and feel hungry. Try small amounts of plain foods, such as soup, rice, pasta and bread.
• Give them paracetamol if they have an uncomfortable fever or aches and pains. Young children may find liquid paracetamol easier to swallow than tablets.
• Use special rehydration drinks made from sachets bought from pharmacies if they're dehydrated. Your GP or pharmacist can advise on how much to give your child. Don't give them antidiarrhoeal and anti-vomiting medication, unless advised to by your GP or pharmacist.

Babies and young children, especially if they're less than a year old, have a greater risk of becoming dehydrated. Read advice about looking after babies and children under five who have diarrhoea and vomiting.

Make sure you and your child wash your hands regularly while your child is ill and keep them away from school or nursery until at least 48 hours after their symptoms have cleared (see Preventing gastroenteritis).

Getting medical advice for your child

You don't usually need to see your GP if you think your child has gastroenteritis, as it should get better on its own, and taking them to a GP surgery can put others at risk.

Call NHS 111 or your GP if you're concerned about your child, or they:

• have symptoms of dehydration, such as passing less urine than normal, being unusually irritable or unresponsive, pale or mottled skin, or cold hands and feet
• have blood in their poo or green vomit
• are vomiting constantly and are unable to keep down any fluids or feeds
• have had diarrhoea for more than a week
• have been vomiting for three days or more
• have signs of a more serious illness, such as a high fever (over 38C or 100.4F), shortness of breath, rapid breathing, a stiff neck, a rash that doesn't fade when you roll a glass over it or a bulging fontanelle (the soft spot on a baby's head)
• have a serious underlying condition, such as inflammatory bowel disease or a weak immune system, and have diarrhoea and vomiting

Your GP may suggest sending off a sample of your child's poo to a laboratory to confirm what's causing their symptoms. Antibiotics may be prescribed if this shows they have a bacterial infection.

How gastroenteritis is spread

The bugs that cause gastroenteritis can spread very easily from person to person.

You can catch the infection if small particles of vomit or poo from an infected person get into your mouth, such as through:

• close contact with someone with gastroenteritis – they may breathe out small particles of vomit
• touching contaminated surfaces or objects 
• eating contaminated food – this can happen if an infected person doesn't wash their hands before handling food, or you eat food that has been in contact with contaminated surfaces or objects, or hasn't been stored and cooked at the correct temperatures (read more about the causes of food poisoning)

A person with gastroenteritis is most infectious from when their symptoms start until 48 hours after all their symptoms have passed, although they may also be infectious for a short time before and after this.

Preventing gastroenteritis

It's not always possible to avoid getting gastroenteritis, but following the advice below can help stop it spreading:

• Stay off work, school or nursery until at least 48 hours after the symptoms have passed. You or your child should also avoid visiting anyone in hospital during this time.
• Ensure you and your child wash your hands frequently and thoroughly with soap and water, particularly after using the toilet and before preparing food. Don't rely on alcohol hand gels, as they're not always effective.
• Disinfect any surfaces or objects that could be contaminated. It's best to use a bleach-based household cleaner.
• Wash contaminated items of clothing or bedding separately on a hot wash.
• Don't share towels, flannels, cutlery or utensils while you or your child is ill.
• Flush away any poo or vomit in the toilet or potty and clean the surrounding area.
• Practice good food hygiene. Make sure food is properly refrigerated, always cook your food thoroughly, and never eat food that is past its use-by date – read more about preventing food poisoning. 

Take extra care when travelling to parts of the world with poor sanitation, as you could pick up a stomach bug. For example, you may need to boil tap water before drinking it.

Young children can have the rotavirus vaccination when they’re two to three months old, which can reduce their risk of developing gastroenteritis.

Read more on how to prevent germs spreading and food and water safety abroad.