A double-blind comparison of the efficacy and safety of droperidol (5 mg), hydroxyzine HCl (50 mg), diazepam (5 mg), and saline placebo, given concomitantly with meperidine (50 or 75 mg) for preoperative medication, was conducted in 280 female patients scheduled for minor gynecologic procedures. Droperidol proved to significantly superior to the other study drugs in alleviating apprehension (83% of patients calm versus 54, 46, and 34% for hydroxyzine, diazepam, and placebo, respectively). Some drowsiness, occurred in 68 percent of the droperidol-treated patients versus 31, 30, and 21 percent of the other 3 groups, respectively. Global evaluations were consistent with these findings. No clinically significant changes were observed in vital signs in any of the study-drug groups. Adverse reactions were unremarkable in all groups. Significantly less nausea occurred with droperidol than with other treatments, and signficantly less vomiting occurred with droperidol or hydroxyzine. Significantly fewer patients in the droperidol group than in the diazepam group required postoperative antiemetics.