Detailed dietary records were obtained from 30 women with the irritable bowel syndrome and 25 healthy, asymptomatic women. Stool transit times and wet stool weights were measured. Analysis of the dietary data revealed no significant difference between energy, protein, fat, carbohydrate, or total fiber intakes. Total dietary fiber intake was 17 g/day in the irritable bowel group and 18 g/day in the control group, but vegetable fiber intake was significantly lower in the patients (6.6 g/day) than the controls (8.2 g/day). Cereal and fruit fiber were comparable for both groups as were the stool transit times and wet stool weights. These results do not support the hypothesis that symptoms of the irritable bowel syndrome are directly related to total or cereal fiber depletion.