RU486 (mifepristone) followed by a prostaglandin (PG) analogue has been marketed in France since April 1990 as a medical alternative to surgery for early pregnancy termination. By law, the drug is used only in the centres approved for voluntary pregnancy termination, and its distribution is strictly controlled. Before being marketed, it was distributed to more than 20,000 women, as part of a training programme for the prescribers. Analysis confirmed an efficacy rate of 95.3%. Failures included incomplete ovular expulsion (2.8%), premature vacuum aspiration (0.7%) and ongoing pregnancy (1.2%). Pelvic pain and malaise were reported as side-effects in 1.6 and 1.2% of the cases respectively. Infectious complications were reported in 0.2% of the cases. Three severe adverse events (one of which was fatal) occurred, including myocardial infarction and ventricular arhythmia, in the hours following PG administration and justify a careful medical monitoring in the centre 3-4 h after administration of PG. For this reason, a trial was undertaken to evaluate the efficacy of an oral form of a PGE1 analogue (misoprostol). When RU486 was followed 36-48 h later by 400 micrograms of misoprostol, the efficacy rate was 96.9%, indicating an efficacy equivalent to that obtained with the other PG analogues. The distribution procedures were adequately followed by the prescribers and by the patients. In summary, RU486 constitutes a safe and efficient medical means of pregnancy termination, provided that the manufacturer's recommendations are properly followed.