The aim of this open prospective randomized study was to compare two non-invasive methods for second trimester abortion using gemeprost pessaries (Cervagem) and dinoproston gel (Cerviprost) concerning effectiveness, time for abortion, consumption of analgesics, infection-rate and side-effects. Forty women admitted for second trimester legal abortion were allocated to treatment with either gemeprost (20) intravaginally or dinoproston (20) intracervically. All patients were pre-treated with a 3 mm in diameter Lamicel tent applied intracervically for about four hours. The success-rate was 95% for gemeprost and 75% for dinoproston within approximately 48 hours. The median abortion time calculated from the insertion of the Lamicel tent for the successful cases was 22 h 0 min for gemeprost and 24 h 5 min for dinoproston (not significant). The shortest abortion time was found among parous women in the Cervagem group. The difference between Cerviprost and Cervagem in parous women was statistically significant. For nonparous women there were no significant differences in abortion time between the two regimes. No significant difference was found in the demand of Pethidin and the infection-rate between the two groups. No major side effects of the treatment were found. Even if no significant difference in successful abortions was found, probably due to the small patient material, Cervagem seems to be the most appropriate of the two non-invasive methods, because of a 95 per cent success-rate within 48 hours, but also due to its simplicity in design.