Most individuals are surprised to learn they are not alone with symptoms of IBS. In fact, irritable bowel syndrome (IBS) affects approximately 15-20% of the general population. It is the most common disease diagnosed by gastroenterologists (doctors who specialize in medical treatment of disorders of the stomach and intestines) and one of the most common disorders seen by all physicians.

Sometimes irritable bowel syndrome is referred to as spastic colon, mucous colitis, spastic colitis, nervous stomach, or irritable colon.

Irritable bowel syndrome is generally classified as a "functional" disorder. A functional disorder refers to a disorder or disease where the primary abnormality is an altered physiological function (the way the body works), rather than an identifiable structural or biochemical cause. It characterizes a disorder that generally can not be diagnosed in a traditional way; that is, as an inflammatory, infectious, or structural abnormality that can be seen by commonly used examination, x-ray, or blood test.

Irritable bowel syndrome is understood as a multi-faceted disorder. In people with IBS, symptoms result from what appears to be a disturbance in the interaction between the gut or intestines, the brain, and the autonomic nervous system that alters regulation of bowel motility (motor function) or sensory function.

Irritable bowel syndrome is characterized by a group of symptoms in which abdominal pain or discomfort is associated with a change in bowel pattern, such as loose or more frequent bowel movements, diarrhea, and/or constipation. Treatment options are available to manage IBS - whether symptoms are mild, moderate, or severe.