Misoprostol, a synthetic prostaglandin E1 analog, has been given both orally and vaginally for induction of labor in the third trimester.1 Vaginal misoprostol has been shown to be more efficacious than oral misoprostol in equivalent doses,2 although there is the worry of uterine tachysystole and hyperstimulation with vaginal doses of 50 µg or higher.2-4 The higher efficacy after vaginal administration may be explained by the pharmacokinetics of the drug. Zeiman et al5 showed that the systemic bioavailability of vaginally administered misoprostol is 3 times higher than that after oral administration. Plasma concentrations of its metabolite, misoprostol acid, peak one to two hours after vaginal application as compared with the peak seen 30 minutes following oral administration, and although peak levels are lower with the vaginal route, they are sustained longer and overall exposure to the drug is increased, perhaps because of the presystemic gastrointestinal or hepatic metabolism that occurs with the oral route. An additional explanation for the higher efficacy could be that there is a direct effect on the cervix that initiates the physiologic events that lead to increased uterine contractility.6 However, there seems to be a trend toward patient preference for the oral route. The sublingual route of administration has not been reported in the literature prior to 2001. Since then and partly because of issues relating to patient preference, investigators started studying the sublingual route of administration of misoprostol. In theory, the sublingual route could mimic vaginal administration pharmacokinetically, although there have been no such reported studies on this route of administration.