Flutamide has been used successfully in the treatment of hirsutism. However, flutamide may cause important side-effects. The aim of this study was to evaluate the clinical and hormonal effects of lowest-dose flutamide therapy. Sixty-one women with hirsutism aged 18-37 years (mean +/- SD 23.4 +/- 5.9 years) were included in the study. Patients received 62.5 mg flutamide once per day for a period of 12 months. A hirsutism score was determined according to a modified Ferriman-Gallwey scoring system. Before therapy, multiscreen blood chemistry, hormonal analysis and complete blood counts were performed. These parameters and hirsutism scares were repeated at 3, 6, 9 and 12 months during therapy. The modified Ferriman-Gallwey scores significantly decreased from 19.1 +/- 4.9 to 5.8 +/- 3.3 during the study (p < 0.0001). The percentage reductions in hirsutism scores (mean +/- SD) were 60.3 +/- 14.4% at 6 months, and 70.3 +/- 13.2% at 12 months. No significant ride-effects or modifications in the menstrual cycles were observed. There were no significant differences in any of the hormone levels during therapy. In conclusion, the lowest dose of flutamide, 62.5 mg/day, is a well-tolerated therapeutic agent and can be used in the treatment of hirsutism.