A diet made low in vitamin E by elimination of foods considered good sources of the vitamin was fed for 13 months to two groups of men engaged in strenuous labor. With a daily average dietary intake of about 9.4 mg of total tocopherols, a progressive decline in blood levels of tocopherol from 1.42 to 0.81 mg/100 ml was observed in the five control subjects. The test group of 30 men received a daily supplement of tocopherol-stripped safflower oil containing 88 g of polyunsaturated fatty acids and 2.3 mg of tocopherols. Average blood plasma levels of tocopherol in this group dropped rapidly from an initial value of 1.01 to about 0.5 mg/100 ml within 5 months and remained relatively stable thereafter. No muscular weakness or other physical symptoms were reported.