The induction of post-conceptional menses needs a technically simple method which would avoid instrumentation of the uterus. One possible method investigated in this study is the abortifacient effect of a single dose long-acting vaginal suppository containing 3.0 mg of (15S)-15-methyl prostaglandin F2 alpha methyl ester. Pregnancy was terminated successfully in 13 of the 14 subjects. Two successful patients required curettage for prolonged bleeding and retained products of conception. Prolonged vaginal bleeding and the uncertainty of endpoints with particular reference to human chorionic gonadotropin (HCG) constitute the major problem with this non-invasive method, and are discussed in the light of the data obtained.