A randomized, double-blind study was performed on 16 women to compare the efficacy of daily subcutaneous (SC) injections of leuprolide acetate (LA; TAP Pharmaceuticals, North Chicago, IL) plus oral placebo tablets (group A, n = 7) with SC LA plus oral medroxyprogesterone acetate (The Upjohn Company, Kalamazoo, MI; group B, n = 9) in the treatment of leiomyomata uteri. Patients in group A had a significant reduction in uterine size from a pretreatment volume of 601 +/- 62 cm3 (mean +/- standard error) to a mean uterine volume of 294 +/- 46 cm3 at 24 weeks of therapy (P less than 0.01). Group B patients had a reduction in uterine volume from 811 +/- 174 cm3 to 688 +/- 154 cm3, which was not statistically significant. However, only one patient in group B experienced hot flashes, whereas six patients in group A had this symptom (P less than 0.01). Both groups demonstrated significant increases in mean hemoglobin concentrations, hematocrits, and serum iron levels at 24 weeks of therapy compared with pretreatment levels.