Diarrhoea is where you frequently pass watery or loose poo. Some people may also have other symptoms, depending on the cause.

It affects most people from time to time and is usually nothing to worry about. However, it can be distressing and unpleasant until it passes, which normally takes a few days to a week.

The excessive loss of water in your poo can also sometimes lead to symptoms of dehydration, which can be serious if it's not recognised and treated quickly.

This topic covers:

If you have diarrhoea you can use our online symptom checker to find out what to do.

When to seek medical advice

Contact your GP or call NHS Direct Wales on 0845 46 47 for advice if you are concerned about yourself or your child.

You should also contact your GP in the situations outlined below, as they may mean an increased risk of a more serious problem.

Read more about diagnosing the cause of diarrhoea.


You should contact your GP or health visitor urgently if your baby has had six or more episodes of diarrhoea in the past 24 hours, or if they've vomited three times or more in the past 24 hours.

You should also seek advice if your baby has any symptoms of dehydration.


Contact your GP if your child has: 

  • had six or more episodes of diarrhoea in the past 24 hours
  • diarrhoea and vomiting at the same time
  • watery poo
  • blood in their poo
  • a severe or continuous stomach ache
  • symptoms of dehydration

You should also contact your GP if your child has persistent diarrhoea. Most cases will pass in five to seven days. 


Contact your GP if you have diarrhoea and:

  • blood in your poo
  • you're persistently vomiting
  • you have lost a lot of weight
  • you've passed a large amount of very watery diarrhoea
  • it occurs at night and is disturbing your sleep
  • you've recently taken antibiotics or been treated in hospital 
  • you have symptoms of dehydration
  • your poo is dark or black - this may be a sign of bleeding inside your stomach

You should also contact your GP if you persistent diarrhoea. In most cases, diarrhoea should pass within two to four day.

Causes of diarrhoea

There are many different causes of diarrhoea, but a bowel infection (Gastroenteritis) is a common cause in both children and adults. 

Gastroenteritis may be caused by:

  • a virus, such as norovirus or rotavirus
  • bacteria, such as campylobacter and Escherichia coli (E. coli), which are often picked up which are often picked up from contaminated food
  • a parasite, such as the parasite that causes giardiasis, which is spread in contaminated water

These infections can sometimes be caught during travel abroad, particularly to areas with poor standards of public hygiene. This is known as travellers' diarrhoea.

Diarrhoea can also be the result of 

See Diarrhoea - causes for more information.

Treating diarrhoea

Most cases of diarrhoea clear up after a few days without treatment, and you may not need to see your GP.

However, diarrhoea can lead to dehydration so you should drink plenty of fluids (small, frequent sips of water) until it passes.

It is very important that babies and small children do not become dehydrated. Your pharmacist may suggest you use an oral rehydration solution (ORS) if you, or your child, are particularly at risk of dehydration.

You should eat solid food as soon as you feel able to. If you are breastfeeding or bottle feeding your baby and they have diarrhoea, you should try to feed them as normal.

Stay at home until at least 48 hours after the last episode of diarrhoea, to prevent spreading any infection to others.

Medications to reduce diarrhoea, such as loperamide, are available. However, these are not usually necessary, and most types should not be given to children.

Read more about treating diarrhoea

Preventing diarrhoea

Diarrhoea is often caused by an infection. You can reduce your risk by making sure you maintain high standards of hygiene. For example, make sure you:

  • wash your hands thoroughly with soap and warm water after going to the toilet and before eating or preparing food
  • clean the toilet, including the handle and the seat, with disinfectant after each bout of diarrhoea
  • avoid sharing towels, flannels, cutlery or utensils with other
  • wash soiled clothing and bed linen separately from other clothes and at the highest temperature possible – for example, 60C or higher for linen – after first removing any poo into the toilet 
  • avoid returning to work or school until at least 48 hours after the last episode of diarrhoea

Traveller's diarrhoea

It's also important to practise good food and water hygiene while travelling abroad, such as avoiding potentially unsafe tap water and undercooked food.

If you're planning a trip abroad, check health advice for the countries you'll be travelling to.

You can do this by visiting the NHS Fit for Travel and Travel Health Pro websites.

Read more about:

Rotavirus vaccination

Rotavirus is a virus that commonly causes diarrhoea in children. A vaccine that helps protect children against rotavirus is now part of the routine childhood vaccination schedule.

This vaccine is given as a liquid that's dropped into a baby's mouth. It's given in two doses, with the first given at two months and another at three months.

Read about the rotavirus vaccine.

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Diarrhoea usually occurs when fluid cannot be absorbed from the contents of your bowel, or when extra fluid is secreted into the bowel, causing watery poo.

Short-term diarrhoea

Diarrhoea is usually a symptom of a bowel infection gastroenteritis), which can be caused by:

Other possible causes of short term diarrhoea include:


Diarrhoea can also sometimes be a side effect of medicines, including:

The patient information leaflet that comes with your medicine should state whether diarrhoea is a possible side effect.

Long-term diarrhoea 

Conditions that can cause persistent diarrhoea include:

Persistent diarrhoea can also sometimes occur after surgery on the stomach, such as a gastrectomy

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Most cases of diarrhoea get better within a week and you may not need to visit your GP.

The information below explains what will happen if you need to see your GP.

Identifying the cause

To identify what is causing your diarrhoea, your GP may ask questions about:

  • what your stools are like – for example, if they are very watery or contain blood
  • how often you need to go to the toilet
  • whether you have other symptoms, such as a high temperature (fever)
  • whether you have been in contact with anyone else who has diarrhoea or recently travelled abroad - this may mean you have picked up an infection
  • whether you have recently eaten out anywhere (as you may have food poisoning)
  • what medication you are taking and if this has recently changed
  • whether you have been stressed or anxious recently

Stool sample

Your GP may ask you for a stool sample so it can be analysed for signs of an infection if you have:

  • persistent diarrhoea that has lasted more than two weeks
  • blood or pus in your stools
  • symptoms that affect your whole body, such as fever or dehydration
  • a weakened immune system, for example because you have HIV
  • recently travelled abroad
  • recently been in hospital or been taking antibiotics

Blood tests

Your GP may suggest you have some blood tests if they suspect your diarrhoea  is being caused by an underlying health condition.

For example, your blood can be tested for signs of inflammation, which may suggest an inflammatory bowel disease.

See Diarrhoea - causes for more information.

Rectal examination

Your GP may recommend a digital rectal examination (DRE) if you have unexplained persistent diarrhoea, particularly if you're over 50.

During a digital rectal examination, your GP will insert a gloved finger into your anus (back passage) and rectum to feel for any abnormalities. It can be useful in diagnosing conditions that affect your rectum and bowels.

Further investigations

If you have persistent diarrhoea and your GP is unable to find the cause, they may refer you to your local hospital for further investigations. For example, you may have:

  • a sigmoidoscopy – an instrument called a sigmoidoscope (a thin, flexible tube attached to a small camera and light) is inserted into your rectum and up into your bowel
  • a colonoscopy – a similar procedure that uses a larger tube, called a colonoscope, to examine your entire bowel
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Diarrhoea will usually clear up without treatment after a few days, particularly if it's caused by an infection.

In children, diarrhoea will usually pass within five to seven days, and will rarely last longer than two weeks.

In adults, diarrhoea usually improves within two to four days, although some infections can last a week or more.

While waiting for your diarrhoea to pass, you can ease your symptoms by following the advice outlined below.

Drink fluids

It is important to drink plenty of fluids to avoid dehydration, particularly if you are also vomiting. Take small, frequent sips of water.

Ideally, adults should drink a lot of liquids that contain water, salt and sugar. Examples include water mixed with juice or soup broth.

If you are drinking enough fluids, your urine will be light yellow or almost clear.

It is also very important that babies and small children do not become dehydrated. Give your child frequent sips of water, even if they are vomiting. A small amount is better than none.

Fruit juice or fizzy drinks should be avoided, as these can make diarrhoea worse in children.

If you are breastfeeding or bottle-feeding your baby and they have diarrhoea, you should continue to feed them as normal.

Contact your GP immediately if you or your child develop any symptoms of dehydration.

Oral rehydration solutions (ORS)

Your GP or pharmacist may suggest using an oral rehydration solution (ORS) to prevent dehydration if you are at risk - for example if you are frail or elderly. ORS can also be used to treat dehydration that has already occurred.

Rehydration solutions usually come in sachets that are available without a prescription from your local pharmacist. They are dissolved in water and replace salt, glucose and other important minerals that are lost through dehydration.


Your GP or pharmacist may recommend an oral rehydration solution for your child if they are dehydrated or at risk of dehydration.

The usual recommendation is for your child to drink an ORS each time they have an episode of diarrhoea. The amount they should drink will depend on their size and weight.

Your pharmacist will be able to advise you about this. The manufacturer’s instructions should also give information about the recommended dose.

You may be able to give your baby an ORS if they become dehydrated, but check with your GP, pharmacist or health visitor first.


Opinion is divided over when and what you should eat if you have diarrhoea. However, most experts agree that you should eat solid food as soon as you feel able to. Eat small, light meals avoiding fatty or spicy foods.

Good examples are potatoes, rice, bananas, soup and boiled vegetables. Salty foods help the most.

You don't need to eat if you've lost your appetite but you should continue to drink fluids and eat as soon as you feel able to.


If your child is dehydrated, do not give them any solid food until they have drunk enough fluids. Once they have stopped showing signs of dehydration, they can start eating their normal diet.

If your child is not dehydrated, offer them their normal diet. If your child refuses to eat, continue to give them fluids and wait until their appetite returns.


Antidiarrhoeal medicines

Antidiarrhoeal medicines may help reduce your diarrhoea and slightly shorten how long it lasts. However, they are not usually necessary. 
Loperamide is the main antidiarrhoeal medicine used, as it has been shown to be effective and causes few side effects.

Loperamide slows down the muscle movements in your gut so that more water  is absorbed from your stools. This makes your stools firmer and they are passed less frequently.

An alternative to loperamide is a different type of antidiarrhoeal medicine called racecadotril, which works by reducing the amount of water produced by the small intestine.

Evidence suggests that this medication may be as effective as loperamide for treating diarrhoea.

Some antidiarrhoeal medicines can be bought from a pharmacy without a prescription.

Check the patient information leaflet that comes with the medicine to find out if it is suitable for you and what dose you should take. Ask your pharmacist for advice if you are unsure.

Do not take antidiarrhoeal medicines if there is blood or mucus in your stools or you have a fever (high temperature). Instead, you should contact your GP for advice.

Most antidiarrhoeal medicines shouldn't be given to children. Racecadotril can be used in children over three months old if it's combined with oral rehydration and the other measures mentioned above, although not all doctors recommend it.


Painkillers will not treat diarrhoea, but paracetamol or ibuprofen can help relieve a fever and a headache.

If necessary, you can give your child liquid paracetamol or ibuprofen.

Always read the patient information leaflet that comes with the medication, to find out if it is suitable for you or your child and find out the correct dose. Children under 16 years old should not be given aspirin.


Treatment with antibiotics is not recommended for diarrhoea if the cause is unknown. This is because antibiotics:

  • will not work if the diarrhoea is caused by a virus
  • can cause unpleasant side effects
  • can become less effective at treating more serious conditions if they are repeatedly used to treat mild conditions

Antibiotics may be recommended if you have severe diarrhoea, and a specific type of bacteria has been identified as the cause.

They may also be used if you have an underlying health problem, such as having a weakened immune system.

Treatment in hospital

Occassionally, hospital treatment may be needed to treat serious dehydration. Treatment involves administering fluids and nutrients directly into the vein (intravenously).

Treating the underlying cause

If you've been diagnosed with a specific condition that's causing your diarrhoea, treating this may help improve your symptoms.

For example:

  • irritable bowel syndrome (IBS) can be treated with changes to your diet and medications– read more about treating IBS
  • inflammatory bowel disease can be treated with medications that help reduce inflammation in the bowel
  • coeliac disease can be treated by excluding foods containing gluten from your diet – read more about treating coeliac disease
  • bile acid malabsorption can be treated with medicaiton that helps stop bile building up in the digestive system

Can probiotics help?

Probiotics are live bacteria and yeasts found in some youghurts and food supplements.

There's some evidence that certain probiotics can slightly shorten a period of diarrhoea, although the evidence isn't yet stong enough to recommend them.

There's also evidence to suggest some probiotics may reduce your chances of developing diarrhoea after taking antibiotics.

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The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
Last Updated: 14/02/2018 13:18:08