This randomized, double-blind trial evaluated the effect of metoclopramide on the pain and analgesic requirements associated with prostaglandin-induced labor for second-trimester termination of pregnancy. After receiving intrauterine prostaglandin, seven women were given intravenous metoclopramide (10 mg), and eight received saline, concurrent with initiation of patient controlled analgesia (PCA). Group differences were assessed with serial visual analogue scale for pain, interval PCA-morphine consumption, and time to fetal delivery. The metoclopramide group used 54% less PCA morphine (24.1 vs 52.0 mg), had lower visual analogue scale scores, and interval morphine consumption at 2, 4, and 6 h after PCA had been initiated, as well as earlier delivery of the fetus when compared with the control group (P less than 0.05). We conclude that a single dose of metoclopramide reduces the pain and PCA-morphine requirements of patients undergoing prostaglandin-induced labor and may facilitate passage of the fetus. Metoclopramide may have a similar application in treating other types of gynecologic pain.