A multicentre, randomized, comparative clinical trial of 200 mg RU486 (Mifepristone) followed 48 h later by either 5 mg 9-methylene PGE(2) vaginal gel (meteneprost) or 600 microg oral PGE(1) (misoprostol) for termination of pregnancy within 28 days of the missed period, was carried out through the Indian Council of Medical Research's (ICMR) network of Human Reproduction Research Centres (HRRCs). A total of 893 subjects were assessed regarding their therapeutic responses to the two different treatment groups. The results indicated a success rate of 84.6% among 453 women treated with RU486 followed by 9 methylene PGE(2) vaginal gel, that was not significantly different from the success rate of 87.7% observed in 440 women treated with RU486 followed by oral PGE(1). The majority of study subjects (90%) started bleeding within 72 h. About 26% of the subjects had started bleeding before the administration of any prostaglandin. The average duration of bleeding in all the subjects was about 7 days. No life threatening side effects were observed among the subjects in two treatment groups. Gastro-intestinal complaints were reported more often by women treated with oral PGE(1) as compared to those treated with 9-methylene vaginal PGE(2) gel; nausea occurred in 25.7% and 19.2%, vomiting in 6.8% and 4.6%, and diarrhoea in 4.8% and 0.9% of the subjects in the 2 treatment groups, respectively. Fever higher than 38 degrees C and severe abdominal pain were reported by 4.2% and 5.0% of all subjects treated, respectively. Intravenous infusion of glucose and saline was required by 6 subjects in each treatment of the prostaglandin treated groups. Blood transfusion was required in 2 subjects, one in each treatment group, for profuse bleeding.