The effect of cisapride on postoperative colonic motility was studied in 40 patients undergoing cholecystectomy under randomized, double-blind conditions. The patients received 10 mg of cisapride or placebo by intravenous injection starting on the day of surgery and repeated every 12 h until the 3rd postoperative day. The return of propagative motility in the colon was visualized by means of radiopaque markers and serial abdominal radiographs. Cisapride induced a significantly earlier return of propulsive motility in the right colon, as indicated by the propagation of markers from the ascending colon to the transverse colon (p less than 0.05). Radiopaque markers reached the descending colon (p less than 0.05) and the rectosigmoid colon (p less than 0.05) significantly earlier in the cisapride group than in controls. The first passage of feces occurred significantly earlier in cisapride-treated patients than in controls (p less than 0.05). The first passage of gas after surgery did not differ significantly between the groups. Our results suggest that cisapride can be used to induce earlier return of propagative motility in the colon after major abdominal surgery.