Objective: Effectiveness of 2-year treatment of hirsutism with low estrogen oral contraceptives (OCs) containing nonandrogenic or antiandrogenic progestogen. Evaluation of changes in plasma lipids. Design: Ten patients treated with desogestrel 150-mu-g + 30-mu-g ethinyl estradiol, 6 with desogestrel 150-mu-g + 50-mu-g ethinyl estradiol, 10 with cyproterone acetate 2 mg + 35-mu-g ethinyl estradiol. Random allocation. Paired comparisons. Control group: 19 normal women, not treated. Setting: Academic tertiary care. Patients: Women with hirsutism (idiopathic and/or polycystic ovary), 24 of 26 completed treatment. Intervention: Two-year treatment. Main Outcome Measures: Hirsutism score, plasma testosterone, and lipids. Results: Initial hirsutism scores (11.8 +/- 0.6 SE) declined with treatment -7.2 +/- 0.4, P < 0.01) to 4.7 +/- 0.6, almost reaching control (3.6 +/- 0.3). Initial plasma cholesterol (4.33 mmol/L +/- 0.30 SE), similar to control (4.78 +/- 0.24), increased slowly over 2 years (+ 2.04 +/- 0.34, P < 0.01). High-density lipoproteins cholesterol (1.05 mmol/L +/- 0.04 SE), similar to control (1.12 +/- 0.07), did not change the 1st year and increased at 2 years (+ 0.57 +/- 0.11, P < 0.01). No differences appeared among treatment groups. Conclusions: Treatment is very effective, 2 years for best results. The OCs tested are equally efficacious. Changes in plasma lipids are of some concern but of difficult interpretation.