Our data indicate that alpha-tocopherol used in an oral dose of 2 g/m2 daily results in a six- to eightfold increase of the vitamin E levels in serum. The occurrence of congestive heart failure in three patients and the observation of significant pathologic changes in endomyocardial biopsies in approximately half of the patients treated with a median cumulative adriamycin dose level of 550 mg/m2 indicate that alpha-tocopherol does not offer substantial protection against adriamycin-induced cardiac toxicity. The antitumor activity of the drug, however, is not compromised by the concomitant administration of the vitamin.