Irritable bowel disease; Functional bowel disease; Irritable colon; Nervous bowel; Spastic bowel; Spastic colitis

The irritable bowel syndrome is defined on the basis of the recently modified Rome III criteria (2006) as the presence of recurrent abdominal pain or discomfort that cannot be explained by structural or biochemical abnormalities at least 3 days per month during the previous 3 months and that is associated with two or more of the following features: pain is relieved with defecation, its onset is associated with a change in the frequency of bowel movements (diarrhea or constipation), or a change in stool form or appearance (loose, watery, pellet like) [1]. Supporting symptoms include the following: altered stool frequency, altered stool form, altered stool passage (straining and/or urgency), mucorrhea, abdominal bloating, or subjective distention.

In the USA, population-based studies estimate the prevalence of irritable bowel...