The objective of the study was to evaluate the efficacy and safety of 800 microg of misoprostol every 12 h, for a period of 36 h for pharmacological abortion. A group of 162 volunteer women with gestations between 50 and 63 days received misoprostol every 12 h up to a maximum of three doses for abortion. Outcome measures assessed included: successful abortion (complete abortion without requiring surgery), side effects, and a decrease in hemoglobin, mean time of vaginal bleeding, mean expulsion time and mean time of returning of menses. Complete abortion occurred in 148 of 162 (91%, 95% confidence interval 87.95) patients. The mean decrease in hemoglobin was statistically significant (p = 0.001). Vaginal bleeding lasted 8.0 +/- 3.2 days, spotting 8.0 +/- 3.5 days, and total bleeding 16 +/- 4.0 days. The mean expulsion time was 8.5 +/- 4.0 h. According to the observed outcomes, 800 microg of misoprostol vaginally could be a valid method to terminate pregnancies up to 9 weeks of gestation.