Six women with acne and six women with hirsutism were treated with the GnRH analog [D-Ser(Bu(t))6] LHRH-(1-9)ethylamide (Buserelin) for 6 months (nasal spray, 1,200 micrograms/day) to suppress ovarian steroidogenesis. All women were eumenorrheic and did not demonstrate any adrenal or ovarian dysfunction. During treatment, ovarian steroids, LH and FSH decreased, while DHEA-S showed minor modifications; the clinical score for both acne and hirsutism showed a significant reduction. Moreover, acne and hirsutism were still well controlled 6 months after therapy. Gonadal function resumed in all patients after discontinuation of therapy. Three patients suffered from hot flashes from the 4th month. These data demonstrate that suppression of ovarian steroid secretion might be an efficient treatment in women suffering from acne or idiopathic hirsutism, indicating that ovarian steroids may have a key-role in the pathogenesis of these conditions.