Digestive health – Diarrhoea


Digestive health – Diarrhoea


Diarrhoea is passing looser or more frequent stools than is normal for you.

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.

What causes diarrhoea?

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

Gastroenteritis can be caused by:

a virus – such as norovirus or rotavirus

bacteria – such as campylobacter and Escherichia coli (E. coli), 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 anxiety, a food allergy, medication or a long-term condition, such as irritable bowel syndrome (IBS).

What to do if you have 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's very important that babies and small children do not become dehydrated.

Your pharmacist may suggest that 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.

When to see your GP

It's important to see your GP if the diarrhoea is particularly frequent or severe, or is associated with other symptoms, such as:

blood in your or your child's poo

persistent vomiting

a severe or continuous stomach ache

weight loss

signs of dehydration – including drowsiness, passing urine infrequently and feeling lightheaded or dizzy

your poo is dark or black – this may be a sign of bleeding inside your stomach

You should also contact your GP if your or your child's diarrhoea is particularly persistent, as this may be a sign of a more serious problem. In most cases, diarrhoea should pass within about a week.

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, you should

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 household members

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

Symptoms associated with diarrhoea 

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

Associated symptoms can include:

stomach cramps

nausea and vomiting


loss of appetite

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

Signs of dehydration

Signs of dehydration in children can include:

irritability or drowsiness

passing urine infrequently

pale or mottled skin

cold hands and feet

they look or feel increasingly unwell

Signs of dehydration in adults can include:

tiredness and a lack of energy

loss of appetite


feeling lightheaded


dry tongue

sunken eyes

muscle cramps

rapid heartbeat

When to seek medical advice

You should also contact your GP in the situations outlined below, as they may mean that you or your child has, or is at risk of, a more serious problem.


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 have 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: 

there is blood in your poo

you are vomiting persistently

you've lost a lot of weight

you have passed a large amount of very watery diarrhoea

it occurs at night and is disturbing your sleep

you have 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 have persistent diarrhoea. Most cases in adults will pass in two to four days.

Causes of diarrhoea 

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

Short-term diarrhoea

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

a virus – such as norovirus or rotavirus

bacteria – such as campylobacter, Clostridium difficile (C. difficile), Escherichia coli (E. coli), salmonella or shigella; these can all cause food poisoning

parasites – such as the Giardia intestinalis parasite that causesgiardiasis

Other possible causes of short-term diarrhoea include:

feelings of anxiety

drinking too much alcohol

a food allergy


damage to the lining of the intestines as a result of radiotherapy


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


antacid medicines that contain magnesium 

some chemotherapy medicines

non-steroidal anti-inflammatory drugs (NSAIDs)

selective serotonin reuptake inhibitors (SSRIs)

statins (cholesterol-lowering medicines) 

laxatives (medicine used to help empty your bowels) 

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

You can also use the medicines A-Z to find out about your medicine.

Long-term diarrhoea 

Conditions that can cause persistent diarrhoea include:

irritable bowel syndrome (IBS) – a poorly understood condition affecting the normal functions of the bowel

inflammatory bowel disease – conditions that cause the gut to become inflamed, such as Crohn's disease and ulcerative colitis

coeliac disease – a digestive condition where you have an adverse reaction to gluten

chronic pancreatitis – inflammation of the pancreas

diverticular disease – where small bulges or pockets develop in the lining of the intestine

bowel cancer – this can cause diarrhoea and blood in your stools

Persistent diarrhoea can also sometimes occur following surgery on the stomach, such as a gastrectomy. This is an operation to remove part of the stomach – for example, as a treatment for stomach cancer.

Diagnosing diarrhoea 

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, such as:

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 have recently travelled abroad, as this may mean you have picked up an infection

whether you have recently eaten out anywhere, as this may mean you have food poisoning

whether you are taking medication and if it 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 a 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 that you have some blood tests if they suspect that an underlying health condition is causing your diarrhoea.

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

Rectal examination

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

During a DRE, your GP will insert a gloved finger into your bottom to feel for any abnormalities. It can be useful for diagnosing conditions that affect your rectum and bowel.

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 investigation.

You may have:

a sigmoidoscopy – an instrument called a sigmoidoscope (a thin, flexible tube with a small camera and light on one end) is inserted into your bottom and up into your bowel

a colonoscopy – a similar procedure that uses a larger tube called a colonoscope to examine your entire bowel

Treating diarrhoea 

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

Ideally, drink a lot of liquids that contain water, salt and sugar. Some examples include water mixed with juice, flavoured soda, and soup broth. If you are drinking enough fluids, your urine will be light yellow or almost clear.

It's also very important for babies and small children not to 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 because they 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 anysymptoms 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 available from your local pharmacist without a prescription. They are dissolved in water and replace salt, glucose and other important minerals that are lost if you are dehydrated.


Your GP or pharmacist may recommend giving your child an ORS if they are dehydrated or at risk of becoming dehydrated.

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 can 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 and avoid 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 they refuse 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, because 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 whether it's 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 and/or you have a high temperature (fever). Instead, you should contact your GP for advice.

Most antidiarrhoeal medicines should not 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 check if it's suitable for you or your child and to find out the correct dose. Children under 16 years of age 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 a weakened immune system.

Hospital treatment 

Occasionally, hospital treatment may be needed if you or your child is seriously dehydrated. Treatment will involve administering fluids and nutrients directly into a vein (intravenously).

Can probiotics help?

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

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

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

Preventing diarrhoea 

To prevent the spread of infections that cause diarrhoea, you should always maintain high standards of hygiene.

You should:

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 others

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

You or your child should also avoid swimming pools for two weeks after the last episode of diarrhoea.

Food hygiene

Practising good food hygiene will help avoid getting diarrhoea as a result of food poisoning. You can do this by:

regularly washing your hands, surfaces and utensils with hot, soapy water 

never storing raw and cooked foods together 

making sure food is kept properly refrigerated 

always cooking your food thoroughly 

never eating food past its use-by date

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

Travellers' diarrhoea

There is no vaccination that can protect you from all possible causes of travellers' diarrhoea. The best way to avoid it is to practise good food and water hygiene while abroad. 

If you are travelling in a country where standards of public hygiene are low, you should avoid:

tap water – water should be boiled for at least one minute if you're not sure whether it's safe to drink

ice cubes and ice cream

raw or undercooked seafood, meat, chicken

foods that might contain uncooked eggs – such as mayonnaise

unpasteurised milk and dairy products – such as cheese

fruit and vegetables with damaged skins


It's generally safe to eat or drink:

food that has been thoroughly cooked and is served piping hot

sealed bottles or cans of water, fizzy drinks and alcohol

fruit and vegetables you peel yourself

tea or coffee

Digestive health