This study has provided evidence for a considerable role of lipid peroxidation in the pathogenesis of murine influenza infection. The virus-induced activation of lipid peroxidation was followed by the enhanced activity of endogenous enzymes of the antioxidative protection system. The preventive effect of an antioxidant and the therapeutical effect of an antihypoxant were recorded in the prevention of murine death due to influenza. The mechanisms of the protective effect of the antihypoxant is due both to its immediate antihypoxant function and its correcting influence on lipid peroxidation.