Vomiting in the postoperative period is common in children after strabismus surgery. One hundred ten pediatric patients, ages 8 months to 14 yr, admitted for outpatient strabismus surgery were enrolled in a randomized, double-blinded study to compare droperidol and metoclopramide to placebo for the prevention of postoperative emesis. Each child was prospectively assigned at random to one of four treatment groups: metoclopramide 0.15 mg/kg, metoclopramide 0.25 mg/kg, droperidol 0.075 mg/kg, or saline control. Drugs were administered intravenously immediately after induction of inhalation anesthesia. No neuromuscular blocking agents were used. Tracheal extubation was performed while patients were still deeply anesthetized. Acetaminophen and meperidine were given in standard doses for postoperative pain to all children. The incidence of vomiting was less in both the droperidol (33%) and metoclopramide 0.25 mg/kg (29%) groups when compared to controls (88%) (P less than 0.01). Patients receiving metoclopramide 0.15 mg/kg had a 68% incidence of vomiting (P not significant). The mean frequency of emesis was reduced in all treatment groups compared with control (P less than 0.05). Patients receiving droperidol and metoclopramide 0.25 mg/kg also had decreased postoperative stays (metoclopramide 201 min; droperidol 213 min) versus control (258 min, P less than 0.05). No child exhibited extrapyramidal symptoms, excessive drowsiness, or agitation. We conclude that metoclopramide in a dose of 0.25 mg/kg, administered prior to the start of surgery, is at least as effective as droperidol in preventing postoperative emesis and can reduce the time to patient discharge compared to control.