Vaginal suppositories containing (15S)-15-methyl prostaglandin F2 alpha methyl ester were administered to 40 subjects, in an attempt to induce an early abortion. All subjects were 49 days or less from their last menstrual period. Ten subjects received a 3-mg suppository followed in 3 hours by a 1 mg suppository, ten subjects received the 1-mg suppository followed in 3 hours by a 3-mg suppository, and twenty subjects received the 3-mg suppository followed in 1 hour by the 1-mg suppository. Twenty-four subjects (60%) had a successful termination of their pregnancy using the two vaginal prostaglandin suppository regimen. All subjects who aborted had 10 percent or less of their pretreatment levels of beta-hCG 7 to 22 days after therapy. Sixteen subjects (40%) did not abort. One of the subjects who failed treatment refused the second suppository due to gastrointestinal side effects and uterine cramping following the insertion of the 1-mg suppository. A second subject had an incomplete abortion and developed mild endometritis. Sixteen subjects reported side effects which included nausea, emesis, diarrhea, uterine cramping requiring analgesia, restlessness, shakiness, and dizziness. The addition of the second vaginal suppository containing this particular prostaglandin analogue did not significantly increase the overall abortifacient activity of this method.