BACKGROUND Trials on functional dyspepsia (FD) have been performed mostly in Western populations. We evaluated the effect of cisapride in Saudi Arabs with FD. METHODS In a double-blind, randomized, placebo-controlled trial patients were treated with cisapride three times daily or matching placebo and assessed at 2 and 4 weeks. RESULTS Cisapride (n = 44) was significantly superior to placebo (n = 45) in improving heartburn, postprandial bloating, epigastric pain, early satiety, epigastric burning, and nausea. The global response to treatment was excellent or good in 86.7% and 26.7% of the cisapride and placebo groups, respectively. Treatment was judged more effective than the previous therapy in 86.4% and 33.3% of those receiving cisapride and placebo, respectively. There were no adverse drug effects. CONCLUSIONS Cisapride is an effective and well-tolerated treatment for FD in Saudi Arabs. Pharmacogenetic factors are unlikely to play any role in its effects.