Introduction
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.
Recovery
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
Babies
Contact Dr. B C Shah urgently for advice if your baby has had six or more episodes of diarrhoea in the past 24 hours.
Children
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
Adults
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
Medicines
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.
Referral
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.
Medicines
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.
Painkillers
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
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