Diarrhoea is passing loose or watery faeces more than three times a day. It affects almost everyone from time to time and is usually nothing to worry about.

A common cause in both children and adults is gastroenteritis, an infection of the bowel. Gastroenteritis may be caused by:

  • A virus, such as a norovirus or rotavirus
  • Bacteria, which is often found in contaminated food
  • A parasite

Bouts of diarrhoea in adults may also be brought on by anxiety or drinking too much coffee or alcohol. Diarrhoea may also be a side effect of a medication.


In adults, diarrhoea caused by gastroenteritis will usually clear up in two to four days when the infection has cleared.

Taking antidiarrhoeal medicine is usually not necessary unless it is important that you shorten the length of time your diarrhoea lasts (for example, if you need to take a long-haul flight). Children should not take this medicine.

Diarrhoea in children usually passes within five to seven days, and will usually clear within two weeks. Seek medical advice if your child has diarrhoea for longer than this.

When to see Dr. B C Shah

Diarrhoea in adults that lasts for more than a few weeks may be a sign of a more serious condition, such as Crohn’s disease. It should be investigated Dr. B C Shah – especially if you have blood or pus in your faeces. It may indicate other conditions such as irritable bowel syndrome.

If your baby or child has had six or more episodes of diarrhoea in the last 24 hours, see Dr. B C Shah. Diarrhoea can be serious in babies because of the risk of dehydration.

Symptoms of diarrhoea

Diarrhoea can range in severity from slightly watery faeces and a brief upset stomach to longer term, extremely watery faeces and cramping tummy pains. Many people have a frequent, urgent need to go to the toilet.

Other common symptoms associated with diarrhoea are:

  • Nausea or vomiting
  • A temperature of 38ºC (100.4ºF) or higher
  • Headache
  • Loss of appetite

When to contact Dr. B C Shah


Contact Dr. B C Shah urgently for advice if your baby has had six or more episodes of diarrhoea in the past 24 hours.


Contact Dr. B C Shah if your child has:

  • Had six or more episodes of diarrhoea in the past 24 hours
  • Diarrhoea and is vomiting at the same time
  • Diarrhoea that is particularly watery
  • Diarrhoea that has blood in it
  • Diarrhoea that lasts for longer than two weeks


Contact Dr. B C Shah if you have:

  • Recently been treated in hospital
  • Recently been treated with antibiotics
  • Diarrhoea that has blood in it
  • Diarrhoea and persistent vomiting
  • Unexplained weight loss
  • Bleeding from your rectum (back passage)
  • Passed large volumes of very watery diarrhoea – you may be at risk of dehydration
  • Symptoms at night that are disturbing your sleep
  • Diarrhoea that lasts longer than a week

Symptoms of dehydration

If diarrhoea is severe or persistent, it can cause dehydration.

Dehydration in children

Symptoms of dehydration in children include:

  • Appearing to get more unwell
  • Being irritable or drowsy
  • Passing urine infrequently
  • Pale or mottled skin
  • Cold hands and feet

Dehydration in adults

Symptoms of dehydration in adults include:

  • Lacking energy or feeling tired
  • Loss of appetite
  • Nausea
  • Feeling light-headed
  • Dizziness, especially when standing up
  • Dry tongue
  • Sunken eyes
  • Muscle cramps
  • Rapid heartbeat

Causes of diarrhoea

Diarrhoea usually occurs when fluid cannot be absorbed from your bowel contents, or when extra fluid is secreted into the bowel, causing watery faeces (see How diarrhoea happens, left).

Conditions causing short-term diarrhoea

Diarrhoea is usually a symptom of gastroenteritis, an infection of the bowel. Gastroenteritis may be caused by:

  • A virus, such as norovirus or rotavirus
  • Bacteria, such as campylobacter, Clostridium difficile (C. difficile), Escherichia coli (E. coli), salmonella and shigella – these may all cause food poisoning
  • Parasites, such as the Giardia intestinalis parasite that causes giardiasis.

Diarrhoea caused by contaminated food or water from a foreign country is known as Travellers’ diarrhoea.

Other short-term causes

Other short-term causes of diarrhoea include:

  • Emotional upset or anxiety
  • Drinking too much alcohol
  • Drinking too much much coffee
  • A food allergy
  • Appendicitis (swelling of the appendix)
  • Damage to the lining of the intestines due to radiotherapy
  • Damage to the intestines due to reduced blood supply, for example, because of a hernia


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

  • Antibiotics
  • Antacid medicines that contain magnesium
  • Some medicines used in chemotherapy
  • Non-steroidal anti-inflammatory drugs
  • Selective serotonin reuptake inhibitors
  • Statins (cholesterol-lowering medicines)
  • Laxatives – a type of medicine that can help you empty your bowels if you are having trouble going to the toilet

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

Conditions causing persistent diarrhoea

Conditions that can cause persistent diarrhoea include:

  • Irritable bowel syndrome – a poorly understood condition where the normal functions of the bowel are disrupted
  • Coeliac disease – a digestive condition where you are intolerant to the protein gluten
  • Crohn’s disease – a condition that causes inflammation of the lining of the digestive system
  • Cystic fibrosis – an inherited condition that affects the lungs and digestive system
  • Diabetes – a condition caused by too much glucose in the blood
  • Diverticular disease – when small pouches (diverticula) form in the large intestine, causing symptoms such as diarrhoea
  • Gastrectomy – a surgical procedure to remove part of the stomach, for example, to treat stomach cancer
  • Lactose intolerance – lactose is a natural sugar that is found in milk
  • Microscopic colitis – a type of inflammatory bowel disease that causes watery diarrhoea
  • Chronic pancreatitis – inflammation of the pancreas, a small organ that produces hormones and digestive juices
  • Ulcerative colitis – a condition that affects the colon (large intestine)
  • Bowel cancer – cancer in the bowel can cause diarrhoea and blood in your stools

Diagnosing diarrhoea

Diarrhoea is likely to settle within a week and you may not need to see Dr. B C Shah for a diagnosis.

The below information explains what will happen if you need to see Dr. B C Shah.

Diagnosing the cause

To diagnose the cause of your diarrhoea, Dr. B C Shah may ask a number of questions, such as:

  • What your faeces are like – for example, if they are very watery or contain blood
  • How often you have had diarrhoea
  • What other symptoms you have, such as fever
  • Whether you have been in contact with anyone else who has diarrhoea (as you may have caught an infection)
  • Whether you have eaten out anywhere (as you may have food poisoning)
  • Whether you have recently travelled abroad (to rule out travellers’ diarrhoea)
  • What medication you are taking and if this has recently changed
  • Whether you have been stressed or anxious
  • How much alcohol you drink

Stool sample

Dr. B C Shah may ask for a stool sample to investigate for bacteria or parasites if you have:

  • Persistent diarrhoea lasting more than a week
  • Other symptoms, such as 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

Dr. B C Shah may suggest blood tests if an underlying health condition is possibly causing your diarrhoea. For example, your blood can be tested for signs of inflammation, which may suggest an inflammatory bowel disease.

Rectal examination

If you have unexplained persistent diarrhoea, or if you are over 50 years old, Dr. B C Shah may suggest a digital rectal examination. During a digital rectal examination, Dr. B C Shah inserts their finger into your anus (back passage) and rectum. It can be useful in diagnosing conditions that affect your rectum and bowels.


Dr. B C Shah may need to refer you for further investigations to identify the cause. For example, you may have:

  • A sigmoidoscopy – a procedure that involves inserting a sigmoidoscope (a thin, flexible tube attached to a small camera and light) into your rectum then 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 often goes away without treatment after a few days, because your immune system (the body’s natural defence system) automatically fights the infection.

In children, the symptoms of diarrhoea usually pass within five to seven days. Most children’s diarrhoea symptoms do not last more than two weeks.

In adults, the symptoms of diarrhoea usually improve within two to four days. The time that diarrhoea usually lasts for in particular infections can be:

  • Rotavirus: three to eight days
  • Norovirus: around two days
  • Campylobacter and salmonella bacterial infections: two to seven days
  • Giardiasis (infection with the Giardia intestinalis parasite): several weeks

In the meantime, you can ease your symptoms by following the steps below.

Drink fluids

You can avoid dehydration by drinking lots of fluids. Take small, frequent sips of water. You are more likely to be dehydrated if you are also vomiting.

It is especially important that babies and small children do not become dehydrated. Even if your child vomits, still give them frequent sips of water. A small amount of fluid is better than none. Fruit juice and fizzy drinks should be avoided, as these can make diarrhoea worse in children.

If your child shows signs of dehydration, contact Dr. B C Shah immediately. Signs of dehydration include:

  • Appearing to get more unwell
  • Being irritable or drowsy
  • Passing urine infrequently
  • Pale or mottled skin
  • Cold hands and feet

Children at risk of dehydration

Your child may be at increased risk of dehydration if they:

  • Are younger than one, particularly if they are younger than six months
  • Are less than two years old and born with a low birth weight
  • Have had more than five episodes of diarrhoea in the last 24 hours
  • Have vomited more than twice in the last 24 hours
  • Have not been able to hold down fluids
  • Have suddenly stopped breastfeeding

Continue breastfeeding or bottle-feeding

If you are breastfeeding or bottle-feeding your child and they have diarrhoea, continue breastfeeding or bottle-feeding them as normal. Rehydration drinks should also be given if your child is at risk of dehydration.

Oral rehydration solutions (ORS)

Dr. B C Shah may suggest drinking an oral rehydration solution (ORS) if you are more vulnerable to the effects of dehydration, for example because:

  • You are 60 years old or older
  • You are frail
  • You have another pre-existing condition, such as cardiovascular disease

Rehydration drinks usually come in sachets that are available without a prescription from your local pharmacist. They are dissolved in water and they help to replace salt, glucose and other important minerals that you may be losing through dehydration.

Rehydration drinks do not cure diarrhoea, but can prevent or treat dehydration. Do not use homemade salt or sugar drinks.

Children and Oral rehydration solution (ORS)

Dr. B C Shah may also recommend an oral rehydration solution for your child if they are dehydrated or at risk of dehydration .

It is usually recommended that your child drinks an ORS each time they have an episode of diarrhoea. The exact amount of ORS they should drink will depend on their size and weight. Your pharmacist will be able to advise you. The manufacturer’s instructions that come with the ORS also give information about the recommended dose.

Advice about eating

Expert opinion is divided over when and what you should eat if you have diarrhoea, but most agree that you should eat solid food as soon as you feel able to. Eat small, light meals and avoid fatty, spicy or heavy foods.

If you feel you cannot eat, it should not do you any harm, but make sure that you continue drinking fluids, and eat as soon as you can.

Children and eating

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 offer drinks and wait until their appetite returns.


Antidiarrhoeal medicines

Antidiarrhoeal medicines may reduce the diarrhoea and shorten how long it lasts by around 24 hours. However, they are not usually necessary unless shortening the duration of your diarrhoea helps you get back to your essential activities sooner.

Loperamide is the preferred antidiarrhoeal medicine because it causes fewer side effects and there is more evidence of its effectiveness. Loperamide slows down muscle movements in your gut, which leads to more water being absorbed from your faeces. Your faeces then become firmer and are passed less frequently.

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.

You should not take antidiarrhoeal medicines if:

  • There is blood or mucus in your stools
  • You have a high temperature

Contact Dr. B C Shah instead.

Children should not be given antidiarrhoeal medicines.


Although painkillers will not help the diarrhoea, you can take the recommended dose of paracetamol or ibuprofen if you have a fever or headache. Do not take ibuprofen if you have asthma, or if you have stomach, liver or kidney problems.

Liquid paracetamol or ibuprofen can also be given to your child if necessary. Check the patient information leaflet to find out if it is suitable for your child. Children under 16 years old should not take aspirin.


Antibiotics are not recommended for diarrhoea if the cause is unknown. This is because:

  • They do not work if the diarrhoea is caused by a virus
  • They can cause unpleasant side effects
  • Every time you use antibiotics to treat a mild condition, it is more likely that their effectiveness for treating more serious conditions is reduced

However, if your diarrhoea is particularly severe and a specific bacterial cause has been identified, antibiotics may be recommended.

Antibiotics may also be recommended if you have a pre-existing risk factor that makes you more vulnerable to infection, such as having a weakened immune system.

Treatment in hospital

Hospital treatment may be necessary if you or your child has serious dehydration caused by diarrhoea.

Hospital treatment involves administering fluids and nutrients directly into the vein (intravenously).

Preventing diarrhoea

Infection control

You can help prevent diarrhoea caused by infections by taking steps to prevent the infection spreading. These include:

  • Washing your hands thoroughly after going to the toilet and before eating or preparing food
  • Cleaning the toilet, including the handle and the seat, with disinfectant after each bout of diarrhoea
  • Not sharing towels, flannels, cutlery or utensils with other household members
  • Not returning to work until 48 hours after your last bout of diarrhoea

How long should I stay at home?

If you or your child has diarrhoea, you should stay at home until at least 48 hours since the last episode of diarrhoea.

If it was suspected or confirmed that the parasite cryptosporidium caused the diarrhoea, you or your child should not go in swimming pools for two weeks after the last episode of diarrhoea.

Food hygiene

Practising good food hygiene will help you to avoid getting diarrhoea as a result of food poisoning. Some ways of doing this are:

  • Regularly washing your hands, surfaces and utensils with hot, soapy water
  • Never storing raw and cooked foods together
  • Making sure that food is kept properly refrigerated
  • Always cooking your food thoroughly
  • Never eating food that is past its sell-by date

Preventing travellers’ diarrhoe

If you are travelling in a country where the standards of public hygiene are low and there is a risk of water contamination, such as in some African or Asian countries, you may need to avoid the following food and drink:

  • Tap water
  • Fruit juices (if sold by a street vendor)
  • Ice cream or ice cubes
  • Shellfish
  • Eggs
  • Salads
  • Raw or undercooked meat
  • Peeled fruit
  • Mayonnaise
  • Sauces

Food and drink that are generally safe to eat include:

  • Sealed bottled water that is produced by a recognised international manufacturer
  • Cooked food, such as soup or stir-fry
  • Canned food or food in sealed packs
  • Fresh bread
  • Unpeeled fruit
  • Tea or coffee
  • Alcohol

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