Diarrhea Patient Information Fact Sheet

What is diarrhea?
Diarrhea is the passing of frequent, loose or liquid stools. The number of times a person usually has bowel movements varies greatly; three times a day may be normal for one person, while three times a week may be normal for another. Diarrhea can be acute, starting suddenly and lasting a short time, or chronic, lasting a long time. A doctor should be consulted after a few days if the diarrhea does not abate, or earlier if it is severe and causing dehydration. Consult your doctor sooner if the person affected is elderly or very young (under 2 years).

What are the symptoms of diarrhea?
The main symptom is an increase in the usual number of bowel movements, resulting in frequent, loose or liquid stools. Bowel movements are often preceded by cramping abdominal pain, which eases after the stool is passed. Sometimes there is an accompanying high temperature, and in severe cases there may also be blood or mucus in the stools.

What causes acute diarrhea?
Diarrhea is a symptom of other conditions and is not a disease in itself. It can be caused by a variety of illnesses and conditions, the most common of which is gastroenteritis. Gastroenteritis is usually caused by a viral infection and is passed easily from one person to another. It can also be caused by bacteria in food; when this happens it is often called food poisoning. Some drugs, such as antibiotics, can cause diarrhea as a side effect. Anxiety can also cause diarrhea temporarily. Excess alcohol can cause diarrhea as a result of large volumes of fluid in the bowel.

What causes chronic diarrhea?
Chronic diarrhea can be a symptom of other illnesses, particularly those affecting the digestive system. Examples include Crohn's disease, irritable bowel syndrome (IBS), diverticulitis, and infection with the HIV virus. Tropical diseases such as cholera, dysentery, and giardiasis can also cause chronic diarrhea. In the developing world these diseases are often fatal in small children. Some stomach operations may cause chronic diarrhea.

Are there any tests necessary?
In some cases of acute diarrhea, your doctor may perform a stool test to determine what is causing it. Examples of instances where a stool test may be necessary include the following:

  • Acute diarrhea  following recent return from abroad, particularly from countries where tropical diseases are known to exist.
  • Severe diarrhea accompanied by other symptoms such as a temperature and feeling generally unwell.
  • Severe diarrhea lasting more than a few days.
  • The presence of blood in the stools.

In chronic diarrhea, further diagnostic tests, such as a barium enema, sigmoidoscopy or colonoscopy may be required. Your doctor will explain these tests to you if you need to have one. These tests may confirm the cause of the diarrhea, which may not necessarily be an infection.

How is diarrhea treated?
Rehydration is very important. Electrolyte solutions (eg, Pedialyte) are used in acute diarrhea to replace lost fluids and salts and are usually available as flavored powder in sachets or liquids that need to be mixed with water before taking. Electrolyte solutions do not cure the diarrhea but are necessary to prevent dehydration, which can be dangerous, particularly in the elderly and young children. Medical advice should always be sought before treating the elderly and young children. Adsorbents (eg, methylcellulose [Citrucel] ) help to adsorb (mop up) toxic substances in cases of infective diarrhea and are also used in chronic diarrhea. Opiate derivatives act by slowing movement through the intestine and should only be taken as a short-term solution. These can be purchased over the counter. Examples include loperamide (Imodium). Another preparation containing diphenoxylate and atropine (Lomotil) can be used in diarrhea associated with cramps; this product contains and opiate (diphenoxylate) and an antispasmodic (atropine) to relieve the cramps. Occasionally, antibiotics may be prescribed, usually for diarrhea associated with a tropical disease. Antibiotics are not usually given in cases of food poisoning.

Self-help measures

  • Avoid dehydration; drink clear fluids, preferably those containing electrolytes and an energy source such as glucose. Simple Gatorade is an option but rehydration sachets or solutions can be bought over the counter from a pharmacist or obtained on prescription from your doctor.
  • Good hygiene, particularly washing your hands thoroughly after going to the toilet, is essential in case the diarrhea is infectious.
  • Do not prepare food for other people, especially babies and old people, while you have acute diarrhea. 
  • A carbohydrate diet that includes boiled potatoes or boiled rice may help.
  • If the diarrhea does not resolve after a few days, seek medical advice.

Last Reviewed: May 2013