Diarrhea: causes and symptoms

Diarrhea can be caused by a temporary problem, such as an infection, or by a chronic problem, such as an intestinal disease.

Some of the most common causes of diarrhea are:

• Viral infections

Many types of bacteria, consumed through contaminated food or water, can cause diarrhea. Common bacteria responsible for diarrhea are campylobacter, salmonella, shigella and coliform.

• Viral infections

Many viruses cause diarrhea, such as rotavirus, Norwalk virus, cytomegalovirus, herpes simplex virus and viral hepatitis.

• Food intolerances

Some people cannot digest a food component, for example lactose, the sugar found in milk.

• Parasites

Parasites can enter the body through food or water and settle in the digestive system. The parasites that cause diarrhea are: giardia lamblia, Entamoeba histolytica, and cryptosporidium.

• Reaction to medications such as antibiotics, blood pressure medications, and antacids containing magnesium

• Intestinal diseases, such as inflammatory bowel disease or celiac disease

• Functional bowel disorders, such as irritable bowel syndrome, which disrupts the normal functioning of the bowel

Some people experience diarrhea after stomach surgery or removal of the gallbladder. The reason may be a change in the speed at which food moves through the digestive system after stomach surgery, or an increase in bile in the intestine after gallbladder surgery.

In many cases, the cause of diarrhea cannot be found. If the diarrhea stops on its own, it is not necessary to do extensive testing.

People visiting foreign countries are at risk of developing ‘travelers’ diarrhea’, which is caused by eating food or drinking water contaminated with bacteria, viruses or parasites. Travelers’ diarrhea is a particular problem for people visiting developing countries. Visitors to the United States, Canada, most European countries, Japan, Australia and New Zealand are not at high risk of developing traveler’s diarrhea.