The relationship between intestinal motor activity and the influence of prostaglandin F2alpha (PGF) and cisapride were investigated during the early postoperative period in 26 patients who underwent abdominal surgery. Records of intestinal motility were made using an infusion catheter. PGF, 0.4 microg/kg per minute, given intravenously over 60 min, and cisapride, 5 mg, given intraintestinally, were administered to 13 patients each, first immediately after the operation, and then after the migrating motor complexes (MMCs) had reappeared following a period of intestinal quiescence. The MMCs were reestablished within the first postoperative day. Both PGF and cisapride stimulated irregular, high-amplitude contractions; however, the MMCs reappeared following these induced contractions only if the drugs were administered just after the postoperative MMCs became evident. These prokinetic drugs did not affect gastrointestinal hormone concentrations, but induced contractile activity even in the early postoperative period. Although the findings of this study demonstrate that these drugs may be useful as prokinetic agents to promote recovery from postoperative ileus just after the reappearance of MMCs in the early postoperative period, their precise mode of action has not been established.