Misoprostol, a prostaglandin E₁ analog, is widely used in the United States for cervical ripening and labor induction. Its use for these indications is not approved by the US Food and Drug Administration. The only Food and Drug Administration–approved indication in the product labeling is the treatment and prevention of intestinal ulcer disease resulting from nonsteroidal anti-inflammatory use. Multiple trials have proved that misoprostol is an effective agent for cervical ripening and labor induction in term pregnancy; however, investigations continue regarding the optimal dose, dosing regimen, and route of administration. Uterine contraction abnormalities are often found in association with higher misoprostol doses. Some trials also indicate increased frequencies of meconium passage, neonatal acidemia, and cesarean delivery for fetal distress in women receiving higher doses of misoprostol. Overall, most trials fail to demonstrate a significant change in the cesarean delivery rate with the use of this agent. Misoprostol is an effective agent for cervical ripening and labor induction when used in a judicious and cautious fashion. (Am J Obstet Gyneol 1999;181:339-45.)