Concentrations of lipid peroxidation products (primary--diene conjugates and secondary--malonic dialdehyde) as well as the activity of the antioxidant system (catalase and superoxide dismutase) were evaluated in 118 patients suffering from type II diabetes mellitus complicated with pyonecrotic affection of the lower limbs. Efficacy of the standard therapy and treatment including intravenous infusion of ozonized physiological solution was studied in 58 and 60 patients, respectively. While the conventional therapy reduces endogenous intoxication, intensity of lipid peroxidation, ozonotherapy produces a prompt and effective decrease in pathological activity of lipid peroxidation, regulates a dynamic balance between pro- and antioxidant systems of the human body and, finally, reduces endotoxicosis severity in diabetic patients.