To evaluate whether vitamin E could act as a useful antioxidant to protect pulmonary nuclei, we compared the preventive effect of orally treated vitamin E on chemically induced lipid peroxidation in the pulmonary nuclei and microsomes of rats. Vitamin E (100 mg/kg) treatment for 6 d suppressed ADP/ascorbate/Fe³⁺-induced lipid peroxidation in the nuclei more strongly than that in the microsomes, while the increase of α-tocopherol level in the nuclei by vitamin E treatment tended to be higher than that in the microsomes. Of unsaturated fatty acid composition in the nuclei and microsomes, only the composition of linoleic acid in the nuclei was significantly decreased by this treatment. These results suggest that vitamin E can act as a useful antioxidant in the pulmonary nuclei.