A double-blind, placebo-controlled study of 60 patients post cesarean delivery was conducted to determine whether nalbuphine reverses the side effects of pruritus and respiratory depression associated with epidurally administered morphine. Patients randomly received either three doses of intravenous nalbuphine or the equivalent volume of saline. Vital signs, sedation, pain, pruritus and oxygen saturation were assessed hourly for 18 hours. There were no statistically significant differences in demographic data, sedation level, pain scores or analgesia requirements. Only three patients had no pruritus, one who received nalbuphine and two who received saline. Five patients had respiratory depression (respiratory rate lower than 10 BPM or oxygen saturation less than 90%); three occurred in the nalbuphine group and two in the saline group. Although theoretically advantageous, nalbuphine, as administered in this study of obstetric patients, offered no prophylactic benefit against the pruritus associated with epidural morphine. Its benefit with regard to respiratory depression remains unclear.