To investigate fecal continence in patients with irritable bowel syndrome (IBS), studies were performed in 43 patients with IBS and 20 healthy subjects. Anorectal pressure was measured with BioLAB monitor of digestive tract and anorectal catheter with solid state manometric transducers. The results were analyzed by computation programs of American Sandhill Company. The sensation of defecation volume (DSV),sensation of defecation urgent volume (DUSV) and maximal tolerable volume (MTV) in the patients with diarrhea predominant type IBS (Dp-IBS) were significantly lower than healthy subjects (P