The effects of cisapride on gastric emptying, esophageal emptying, and gastrointestinal symptoms were evaluated in 8 patients with progressive systemic sclerosis who had delayed gastric emptying of the solid or liquid component of a meal, or both. A double-isotope technique was used to measure gastric emptying, and esophageal emptying was measured as the time for a bolus of the solid meal to enter the stomach. Gastrointestinal symptoms were assessed by a questionnaire. On 2 days each patient received cisapride (10 mg) or placebo intravenously, 5 min before an esophageal and gastric emptying test. After these 2 days each subject took cisapride (10 mg q.i.d., p.o.) for 1 mo. Cisapride improved solid and liquid gastric emptying (p less than 0.001), but had no significant effect on esophageal emptying (p less than 0.1). Upper gastrointestinal symptoms were reduced after cisapride (p less than 0.001), and no side effects were reported. These results indicate that gastroparesis is a treatable cause of morbidity in progressive systemic sclerosis.