A low tolerance for pain has been postulated as a factor in the expression of symptoms in patients with irritable bowel syndrome. This has been based on previous work demonstrating reduced intestinal thresholds for rectal pain induced by balloon distention in patients with irritable bowel syndrome. As the disease may alter the rectal response to distention, inferences regarding pain perception and reporting behavior cannot be drawn from these data. In this study, using electrocutaneous stimulation, we found that patients with irritable bowel syndrome had pain reporting behavior comparable to patients with Crohn's disease. Both patient groups were less likely than normals to report a noxious stimulus as painful. This suggests that pain perception and reporting is attenuated in patients with chronic abdominal pain and, accordingly, a generalized reduction in the threshold for reporting pain is not a factor in the expression of symptoms in the irritable bowel syndrome.