Alpha-tocopherol (vitamin E) has been used to treat patients with benign breast disease. To evaluate the efficacy of this treatment, a randomized, double-blind placebo-controlled study was performed on 128 women with confirmed mammary dysplasia. Patients were treated with placebo or 150, 300, or 600 IU of d, 1 α-tocopherol per day for two months; breast examinations, sonography, and thermography were performed in the midluteal phase of the menstrual cycle before and after treatment. No significant objective effects to treatment were noted in any of the parameters monitored. In addition, serum concentrations of estradiol, progesterone, dehydroepiandrosterone sulfate, and testosterone were measured before and after treatment. There were no significant effects on concentrations of these hormones. From this study, d, 1 α-tocopherol does not seem to be beneficial in the treatment of patients with mammary dysplasia.