To establish whether cisapride is beneficial in children with intractable constipation, an open trial was performed. Chronically constipated children who had failed at least 12 weeks of medical therapy received cisapride at a dose of 0.2 mg/kg/dose TID for 12 weeks. Children with pelvic floor dyssynergia were excluded. Patients were followed prospectively for at least 12 months. Thirty children were initially enrolled, and 27 (14 boys, 13 girls) completed the study. At the end of 12 weeks of cisapride treatment, there was a significant increase in the number of bowel movements per week (1.43 +/- 0.52 to 6.48 +/- 4.16; p < 0.05) and significant decreases in the number of accidents per day (2.86 +/- 2.71 to 0.52 +/- 1.23; p < 0.05) and doses of laxatives used per week (14.33 +/- 5.84 to 3.37 +/- 7.10; p < 0.05). Encopresis disappeared in 65.2% of cases (p < 0.0001) and improved in 26%. Sixty-nine percent of the patients stopped using laxatives (p < 0.001). After 12 weeks 18 patients (66.6%) were asymptomatic, seven (25.9%) showed some improvement in bowel movement frequency and number of accidents, and two (7.4%) showed no improvement. The cisapride was well tolerated. After long-term follow-up (20 +/- 9.8 months), 37% of patients had recovered (asymptomatic and off laxatives and cisapride) and 29.6% were still asymptomatic but were using laxatives or cisapride. There were no differences in baseline characteristics between recovered and nonrecovered patients. We conclude that cisapride is effective in the treatment of some children with intractable constipation without pelvic floor dyssynergia.