Therapeutic abortion was induced in 100 women in early pregnancy (less than 56 days' amenorrhoea) with a combination of the antigestagen mifepristone (RU 486) and a synthetic prostaglandin analogue, gemeprost. Mifepristone in oral doses of 400-600 mg was followed 48 h later by a gemeprost vaginal pessary (0.5-1.0 mg). Bleeding was induced in all women 22-70 h after the mifepristone dose and although bleeding continued for 4-43 days (median 12) the total measured blood-loss was only a median of 72.5 ml (range 15-398). Complete abortion occurred in 95 women. Surgical evacuation of the uterus for minimum debris was required in the remaining 5. Only 10 women had diarrhoea or pain that required opioid analgesia. The combination of mifepristone and gemeprost provides a safe and effective alternative to surgical evacuation of the uterus for therapeutic abortion in early pregnancy.