Objective: To study pharmacokinetics of prostaglandin E1 analogue, misoprostol in plasma and colostrum after postpartum oral administration.Study Design: Twenty women received 600 microg doses of misoprostol orally after delivery. Plasma levels of the principal metabolite, misoprostol acid, were measured at 2, 10, 20, 30, 40, 50, 60, 90, 120, 180, 240 and 300 min (48 samples).