Irritable bowel syndrome (IBS) is the most common disorder in patients seen by gastroenterologists. Twenty subjects with IBS diagnosed with the Rome criteria were treated for 12 weeks with 20-40 mg/day of paroxetine (mean dose=31 mg/day). At baseline, 10 patients had a lifetime history of an anxiety disorder, and 10 patients did not have such a history. Both groups had similar improvement in abdominal pain, constipation, diarrhea, incomplete emptying, and bloating/ abdominal distension. Paroxetine was very well tolerated.