Background: There are no controlled studies assessing the effect of metoclopramide and droperidol administered epidurally for the prevention of nausea and vomiting associated with epidural morphine. This study was undertaken to compare the effectiveness of continuous epidural metoclopramide and droperidol in reducing nausea and vomiting associated with epidural morphine. Methods: Ninty patients undergoing elective gynecologic surgery were randomly assigned to one of three study groups; Group A(n=30) patients received continuous infusion of epidural morphine(6.0 mg/day) following a bolus loading dose of 3.0 mg; Group B(n=30), epidural mixture of morphine and droperidol(5.0 mg/day) following a bolus loading dose(morphine 3.0 mg, droperidol 1.5 mg); Group C, (n=30), epidural mixture of morphine and metoclopramide(20 mg/day) following a bolus loading dose(morphine 3.0 mg, metoclopramide 10 mg). For the 24 postoperative hours, the incidence of nausea and vomiting, degree of pain, level of sedation and other adverse effects were evaluated. Results: Incidence of nausea and vomiting, and number of patients who required antiemetic therapy were significantly less in Group B and C than in Group A(P<0.05). Patients in Group A and C were less sedated than those in Group B. Conclusions: We conclude metoclopramide is more effective than droperidol for postoperative nausea and vomiting due to its lower of sedative effect.