Diarrhoea can be described as an increase in the frequency of bowel movements or loose watery bowel movements. Although both changes in frequency of bowel movements and looseness of stools can occur separately, they are usually seen together. This looseness in stools which can vary from slightly soft to watery occurs due to an increase of water content in the stool, most commonly due to an infection of the digestive tract. This medical condition is a common reason for people to seek emergency medical advice.

A number of factors can cause Diarrhoea such as:

1. Viruses: These include Norwalk virus, cytomegalovirus, and hepatitis virus. Rotavirus is the most common cause of diarrhoea in children.

2. Bacteria, protozoa and parasites: These can be spread through contaminated food and water, e.g., typhoid, cholera, etc.

3. Medications: A number of commonly prescribed medications including antibiotics can cause diarrhoea.

4. Lactose intolerance: People who lack enzyme lactase are unable to digest milk protein lactose that is present in dairy products, leading to diarrhoea after eating such foods.

5. Surgery: After an abdominal surgery or gall bladder surgery.

6. Chronic bowel infection: Chronic diarrhoea can occur due to chronic bowel infection e.g., tropical sprue, inflammatory bowel disease (Crohn’s disease and ulcerative colitis) and bowel cancer.