Main Entry: irritable bowel syndrome

Function: noun

: a chronic functional disorder of the colon that is of unknown etiology but is often associated with abnormal intestinal motility and increased sensitivity to visceral pain and that is characterized by diarrhea or constipation or diarrhea alternating with constipation, abdominal pain or discomfort, abdominal bloating, and passage of mucus in the stool—abbreviation IBS; called also irritable colon, irritable colon syndrome, mucous colitis, spastic colon