The effects on gastric emptying and gastrointestinal symptoms of treatment with cisapride alone and in combination with domperidone were investigated in 25 patients with chronic idiopathic dyspepsia. In a double-blind study, 9 patients were randomly assigned to receive cisapride 2.5 mg three times daily, and 8 patients to receive placebo. After 7 days of treatment, gastric emptying was significantly accelerated and the score of gastrointestinal symptoms was significantly reduced in patients treated with cisapride. Placebo treatment had no significant effect. A randomized, double-blind crossover study of 8 patients compared the effects of combined treatment with cisapride 2.5 mg plus domperidone 10 mg three times daily for 7 days against the effects of cisapride plus placebo. Administration of cisapride plus domperidone gave significantly higher gastric emptying and lower gastrointestinal symptoms than cisapride plus placebo.