We investigated the effect of cisapride, a gastroprokinetic agent, on the obstructed gastric mucosal hemodynamics induced by indomethacin using an organ reflectance spectrophotometry system in rats. Indomethacin (10 mg/kg, i.v.) reduced both the gastric mucosal blood volume and the gastric mucosal blood oxygenation. Pretreatment with cisapride (0.1 mg/kg, i.v.) prevented these deteriorations. The presently-clarified gastric mucosal protective effect of cisapride may contribute to its therapeutic efficacy.