Perimenopausal abnormal bleeding is one of the most common gynecological problems. We have assessed the effectiveness of danazol 200 mg daily for 3 months in 42 patients with perimenopausal abnormal bleeding without any previous treatment and in 23 patients previously treated with norethisterone or medroxyprogesterone acetate but with a recurrence of bleeding 2 months after the end of the treatment. In the overall population treated by danazol at the end of treatment we had: bleeding normalized in 88.2% and hysteroscopic patterns, showing regression of hyperplasia in 95% of cases. The endometrial effects were maintained 2 months after the end of treatment with an increase of the hyperplastic pictures at 4 (26%) and up to 12 months (60%). We had amenorrhea in 10% of patients at the end of treatment and in 2 cases only treatment was discontinued for severe side effects. The comparison of these better results with those obtained by progesterone agents and with those of a preliminary experience with GnRH agonists had led us to consider the importance of an additional endometrial effects exerted by danazol. Particularly the immunosuppressive properties of this drug, as we have shown in "in vitro" conditions, can determine a decreased secretion of growth factors by local immune cells which in turn can further explain the endometrial antiproliferative action of this drug.