Maintenance treatment with cisapride was evaluated in 298 patients in whom reflux oesophagitis had been healed with antisecretory drugs. Initially, 34% of the patients had grade-I oesophagitis, 33% had grade II, and 33% had grade III. The patients were treated with 20 mg cisapride twice daily or placebo for 6 months or until endoscopic relapse was shown if this occurred earlier. Survival analysis showed that cisapride significantly prolonged the time to endoscopic relapse in grade-I patients (P = 0.02). The intergroup difference in symptomatic relapse in all patients was also significant (P = 0.010). The effect of cisapride was less clearcut in grade II or III, and/or in patients healed with omeprazole. Factors associated with early relapse were placebo therapy, prior omeprazole therapy, duration of pre-trial symptomatic period, and initial endoscopic severity grade. Adverse experiences were limited; diarrhoea was reported by 9% of the cisapride patients.