We report the results of a controlled, randomized, prospective, 'double blind' evaluation of the effect of danazol treatment in 120 patients after hysteroscopic endometrial resection. After endometrial resection, the women were allocated to 1 of 3 groups: Group A- placebo; Group B - high-dose danazol (600 mg daily); Group C - low-dose danazol (200 mg daily) plus placebo tablets. Tablets were specifically manufactured for the study, were identical in appearance, and were supplied in individual prepackaged boxes. The duration of treatment was 3 months and patients' compliance was noted. Amenorrhoea, dysmenorrhoea and premenstrual tension symptoms were assessed for each group by 1 or 2 independent gynaecologists at follow-up intervals of 6 weeks, 3, 6 and 12 months. A statistically-significant increased rate of amenorrhoea was found in patients who received treatment with the higher-dose danazol (600 mg day) following endometrial resection. While not statistically significant, the same trend was noted with the low-dose danazol. This result should influence our clinical management of women with menorrhagia, and the long-term results on the same cohort of patients are awaited with interest.