In gastroenterology, irritable bowel syndrome (IBS) is a functional bowel disorder characterized by mild to severe abdominal pain, discomfort, bloating and alteration of bowel habits. In some cases, the symptoms are relieved by bowel movements. Diarrhea or constipation may predominate, or they may alternate (classified as IBS-D, IBS-C or IBS-A, respectively). IBS may begin after an infection (post-infectious, IBS-PI) or a stressful life event. Other functional or pain disorders and certain psychological conditions are more common in those with IBS.
