A clinical comparative study between treatment with norethisterone enanthate, and treatment with estradiol enanthate and dehydroxiprogesterone was done to study the differences in effectiveness, changes in menstrual cycle, and side effects of the 2 preparations. Duration of investigation was of 15 months, for a total of 824 cycles. Among the 35 patients treated with norethisterone enanthate there were no pregnancies, and the drug was well accepted. There were a few cases of amenorrhea and of spotting; both manifestations disappeared spontaneously. In 65% of patients the menstrual cycle was longer than usual. 25 patients were treated with the bihormonal preparation; there was 1 pregnancy. Cycles were very close together, and lasted about 6-8 days. There were a few cases of spotting. Side effects were similar with both treatments, and never serious.