Irritable Bowel Syndrome (IBS), also known as spastic colon, recurring symptoms of constipation, diarrhea, and abdominal cramping that appear without a clear cause. IBS accounts for 30 to 50 percent of patient visits to gastroenterologists (physicians who specialize in disorders of the intestinal tract).

The diarrhea associated with IBS is not true diarrhea in that there is no increase in stool volume. Patients sometimes pass mucus with the stools and have a sensation of incomplete evacuation of the bowels following defecation.

Recurring IBS has been associated with stress, although abdominal distress is a common reaction to anxiety in many people who do not suffer from IBS.

Physicians diagnose IBS only after conducting a series of tests that rule out other gastrointestinal disorders, such as inflammatory bowel disease, intestinal parasites, and polyps. These tests include a barium enema, stool parasite culture, and sigmoidoscopy, examination of the lower intestines with a hollow, tubelike instrument passed through the anus.

There is no cure for IBS and treatment focuses on alleviating symptoms. High fiber diets or antispasmodic drugs may relieve constipation, and antidiarrheal drugs may alleviate prolonged diarrhea. Although there is no scientific evidence linking irritable bowel syndrome and the amount of fiber in the diet, some people benefit from eating a high-fiber diet, while others find reducing their carbohydrate intake helps.