BACKGROUND/AIMS: Altered gallbladder motility is regarded as one of the important factors involved in the formation and recurrence of gallstones. Previous studies have suggested that cisapride increases postprandial gallbladder contraction and may therefore be theoretically useful in preventing stone recurrence. The aim of our study was therefore to investigate the effect of cisapride on gallbladder motility in stone-free patients after extracorporeal shock-wave lithotripsy, as compared to healthy volunteers pair-matched for age and sex. METHODS: Each subject received cisapride or placebo in a double-blind, cross-over, random order. Gallbladder volumes were measured by ultrasonography in the fasting state and after intake of a standard liquid meal. Plasma cholecystokinin levels were determined by radioimmunoassay. RESULTS: Fasting gallbladder volumes were smaller in patients as compared to volunteers (20.7 +/- 1.3 ml vs. 46.0 +/- 9.2 ml; p < 0.05) but were not modified by cisapride (21.1 +/- 1.7 ml vs. 58.6 +/- 11.3 ml). The maximal postprandial decrease in gallbladder volume was similar in patients and volunteers (64.5 +/- 12% vs. 62 +/- 10%; NS) and was not significantly altered by cisapride (59 +/- 9.4% vs. 54 +/- 9%; NS). In patients, cisapride increased integrated postprandial gallbladder volume by accelerating gallbladder refilling as compared to placebo by 37 +/- 15% (p < 0.05). Integrated cholecystokinin plasma levels were similar in patients and volunteers and were 13.4 +/- 4.7% higher after cisapride as compared to placebo (p < 0.05). CONCLUSIONS: The results of this study suggest that cisapride does not alter postprandial gallbladder contraction but accelerates gallbladder refilling in patients free from gallstones after extracorporeal shock-wave lithotripsy. This effect of cisapride is probably due to an acceleration of gastric emptying also causing a secondary enhanced cholecystokinin release.