The effect transcutaneous oestradiol for four months supplemented by medroxyprogesterone (Perlutex) from the 12th to 26th day of every month was assessed in an open uncontrolled prospective investigation in 34 women with menopausal symptoms and follicle stimulating hormone greater than 40 international units and luteinizing hormone greater than 25 international units. A marked effect was found on sweating and hot flushes and other menopausal complaints as expressed by Kupperman's menopausal index. Serum oestradiol increased during the first two months to follicular phase values and this was followed by an unexplained decrease after the fourth month which did not, however, result in aggravation of the symptoms. No alterations were found in steroid-hormone-binding globulin, lipids and body weight. Whether the patients placed the plasters in the hip or abdominal regions was found to be of no significance. Seventeen patients had no side effects of the treatment. Nine patients had transient skin symptoms which disappeared spontaneously. Five patients had mastalgia which disappeared after reduction of the Perlutex dose. One patient developed metrorrhagia. A total of three patients abandoned the treatment: one on account of skin symptoms, one on account of high blood pressure and a third on account of psychiatric symptoms which were unrelated to the treatment. A total of 28 patients wanted to continue treatment after the fourth month.