The intravaginal administration of prostaglandin E 2 (PGE 2) in repeated doses of 20 mg was evaluated for efficacy and safety in 400 midtrimester pregnancy terminations. Patients were assigned to three treatment groups. Group A (232 patients) received PGE 2 alone, Group B (106 patients) had prior intracervical laminaria insertion, Group C (62 patients) received both laminaria and continuous intravenous oxytocin infusion. Complete abortion was achieved in 328 cases (82 per cent) and there were 13 failures (3.3 per cent). Mean instillation to abortion times was 13.0 ± 0.4 SEM hours. Differences among the treatment groups were not statistically significant but outcome was more favorable in pregnancies of 16 to 19 weeks' gestation as compared with those between 13 and 15 weeks. Gastrointestinal symptoms and temperature elevation constituted the most frequent side effects. Excessive blood loss occurred in 11 cases (2.8 per cent) and live births were encountered in 12 cases (3.0 per cent). Vaginal PGE 2 is felt to be particularly acceptable for the termination of pregnancies of 16 to 19 weeks' gestation.