The combination of 2 mg cyproterone acetate, a pronounced antiandrogenic substance, in combination with 0.05 mg ethinyl estradiol has undergone intensive multiphasic clinical evaluation. The preparation with the trade name Diane@ has proven to be not only a reliable contraceptive, but also a very potent drug for the treatment of both acne and seborrhea, and of milder cases of hirsutism. The effect of Diane@ on markedly increased hair growth was not so pronounced. In addition to the presentation of the most pertinent steps of the clinical investigation of Diane@, the possible mode of actions of antiandrogens alone and in combination with an estrogen is discussed.