Why people get diarrhea

Diarrhea is a symptom defined as passing frequent loose, watery stools. It is associated with the loss of water and electrolytes (e.g., potassium, sodium, magnesium) from your body. People with diarrhea often have increased number of bowel movements. Diarrhea is defined as passing more than 200 g (about 7 oz) of stool every 24 hours, and some people may pass more than 950 g (32 oz) in a 24-hour period.

Acute diarrhea lasts less than 14 days. Most people experience acute diarrhea at one time or another. Persistent diarrhea lasts more than 14 days but less than a month. Chronic diarrhea lasts longer than a month. Both persistent and chronic diarrhea can be a sign of more serious problems, such as medical conditions.

Diarrhea occurs when the contents in your digestive system move so quickly through the digestive system that the intestines don't have enough time to absorb the fluids, or when the digestive system produces extra fluid. The result is stools that contain excess fluids, making them loose and watery.

A number of causes and circumstances can lead to diarrhea. These include:

• bacterial infections (e.g., E. coli and salmonella - common causes of food poisoning)
• viral infections (e.g., Norwalk-like or rotavirus)
• parasite infections (e.g., Giardia)
• medical conditions that affect the stomach and intestines, such as Crohn's disease, ulcerative colitis, Celiac disease, or irritable bowel syndrome (IBS)
• medications such as antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), magnesium-containing antacids, blood pressure medications, and antidepressants
• alcohol
• food intolerance (e.g., artificial sweetener or lactose intolerance) or food allergies
• radiation or chemotherapy
• stress
• menstruation
• surgery, such as after abdominal surgery or gallbladder removal surgery

Most of the time, you don't have to visit your doctor to address the diarrhea. But if diarrhea lasts more than 3 days, or if you experience any other symptoms (e.g., bloody or black stools, fever, severe abdominal pain), you should see your doctor.