Background:Gastroesophageal reflux is a common condition that in infants may lead to serious complication. This study assessed the efficacy and safety of oral cisapride suspension in the treatment of children 6 weeks to 2 years old with daily regurgitant reflux.Methods:A randomized, prospective, double-blind, placebo-controlled clinical trial was conducted at three study sites. After a 1 week baseline assessment, 45 infants 6 weeks to 2 years old were randomized to a double-blind trial in which they received a 6 week course of cisapride (0.2 mg/kg q6h) or a placebo suspension. Efficacy was assessed with 24 hour esophageal pH monitoring, esophageal manometry, and esophageal biopsy before and after the treatment period. A diary of regurgitation frequency and severity was kept by the parents. Safety was assessed by adverse event monitoring and standard laboratory measurements.Results:Compared with placebo, cisapride significantly (p< 0.05) reduced the mean duration of upright and supine reflux episodes. Compared to baseline, cisapride significantly reduced the mean duration of the longest reflux episode, and placebo increased the mean number of reflux episodes longer than 5 minutes. Cisapride was not significantly different from placebo for the following mean measurements: percent of total time pH <4, number of reflux episodes, lower esophageal sphincter pressure, swallow pressure, regurgitation frequency or global evaluation scores.Conclusions:Cisapride is a safe, well tolerated prokinetic agent that improves the esophageal clearance of refluxed gastric acid in children under the age of 2 years.