Sixteen patients, each receiving 100 mg of dapsone per day, were studied for evidence of hemolysis. Vitamin E (dl-alpha tocopherol acetate), 800 mg/day, was then administered for up to three months, and dapsone therapy was continued at the same dose. Hemolysis factors were reexamined immediately prior to cessation of vitamin E therapy. No substantial change was demonstrable for levels of hemoglobin, reticulocyte count, and haptoglobin at the end of vitamin E therapy, despite a significant rise in serum vitamin E levels. Erythrocyte survival measured in four patients before and at the end of vitamin E therapy also showed no substantial change. Erythrocyte Heinz body count, however, fell in nine of 15 patients studied, and none showed an increase in this measurement while receiving vitamin E. We conclude that in patients receiving dapsone at 100 mg/day, vitamin E therapy at 800 mg/day does not substantially ameliorate the hemolytic effect of this drug.