Ondansetron and droperidol are both effective in the prevention of postoperative nausea and vomiting (PONV). In this randomized, double-blind study, 80 inpatients scheduled for minor gynecologic surgery received either ondansetron 8 mg intravenously (i.v.) or droperidol 2.5 mg i.v. 5 min prior to induction of isoflurane-narcotic anesthesia. PONV was absent in 68% of the patients after ondansetron and in 88% after droperidol (P < 0.05). The respective times of complete arousal from anesthesia were 171 min and 229 min (P < 0.001). After ondansetron and droperidol, the incidence of severe drowsiness, restlessness, anxiety, or dizziness was 5% and 28%, respectively (P < 0.01). Thus after minor gynecologic surgery, droperidol 2.5 mg i.v. was superior to ondansetron 8 mg i.v. in the prevention of PONV. However, relative to ondansetron, droperidol entailed an average 1-h delay in recovery from anesthesia.