In a preliminary study, alpha-tocopherol supplementation was effective in reducing specific symptoms of the premenstrual syndrome (PMS). To confirm these findings, we performed a randomized, double-blind study using d,alpha-tocopherol and placebo in a carefully screened population of women with PMS. Standardized PMS questionnaires were administered in the luteal phase of the menstrual cycle to all subjects, before and after daily treatment with 400 IU d,alpha-tocopherol or placebo for three cycles. Of the 46 subjects enrolled, 41 completed the clinical trial. A significant improvement in certain affective and physical symptoms was noted in subjects treated with d,alpha-tocopherol.