Diarrhea

Diarrhea means that you have loose, watery stools more often than you normally have regular bowel movements. You may also have cramps, bloating, nausea, and an urgent need to have a bowel movement. Causes of diarrhea include bacteria, viruses, or parasites, certain medicines, food intolerances. and diseases that affect the stomach, small intestine, or colon. In many cases, no cause can be found.

Although usually not harmful, diarrhea can become dangerous or signal a more serious problem if it does not resolve within a few days. You should talk to your doctor if you have a strong pain in your abdomen or rectum, a fever, blood in your stools, severe diarrhea for more than 3 days, or symptoms of dehydration.

Acute diarrhea may be caused by a bacterial, viral, or parasitic infection. Chronic diarrhea is usually related to a functional disorder such as irritable bowel syndrome or an intestinal disease such as Crohn’s disease.

Diarrhea occurs when the food and fluids you ingest pass too quickly or in too large an amount — or both — through your colon. Normally, your colon absorbs liquids from the food you eat, leaving a semisolid stool. But if the liquids from the foods you eat are not absorbed, the result is a watery bowel movement.

A number of diseases and conditions can cause diarrhea. Common causes of diarrhea include:

• Viruses. Viruses that can cause diarrhea include Norwalk virus, cytomegalovirus, and viral hepatitis. Rotavirus is a common cause of acute childhood diarrhea.
• Bacteria and parasites. Contaminated food or water can transmit bacteria and parasites to your body. Parasites such as Giardia lamblia and cryptosporidium can cause diarrhea. Common bacterial causes of diarrhea include campylobacter, salmonella, shigella, and Escherichia coli. Diarrhea caused by bacteria and parasites can be common when traveling in developing countries and is often called traveler's diarrhea.
• Medications. Many medications can cause diarrhea. The most common are antibiotics. Antibiotics destroy both good and bad bacteria, which can disturb the natural balance of bacteria in your intestines. This disturbance sometimes leads to an infection with bacteria called Clostridium difficile, which also can cause diarrhea. Cancer drugs and antacids containing magnesium can all cause diarrhea.
• Lactose intolerance. Lactose is a sugar found in milk and other dairy products. Many people have difficulty digesting lactose and experience diarrhea after eating dairy products.Your body makes an enzyme that helps digest lactose, but for most people, the levels of this enzyme drop off rapidly after childhood. This causes an increased risk of lactose intolerance as you age.
• Fructose. Fructose, a sugar found naturally in fruits and honey and added as a sweetener to some beverages, can cause diarrhea in people who have trouble digesting it.
• Artificial sweeteners. Sorbitol and mannitol, artificial sweeteners found in chewing gum and other sugar-free products, can cause diarrhea in some otherwise healthy people.
• Surgery. Some people may experience diarrhea after undergoing abdominal surgery or gallbladder removal surgery.
• Other digestive disorders. Chronic diarrhea has a number of other causes, such as Crohn's disease, ulcerative colitis, celiac disease, microscopic colitis and irritable bowel syndrome.

In many cases, the cause of diarrhea cannot be found. As long as diarrhea goes away on its own within 1 to 2 days, finding the cause is not usually necessary.

See your doctor if diarrhea lasts more than a few days, or you have signs of dehydration, high fever, severe abdominal pain, or blood or black, tarry stools.