Parameters characterizing chemiluminescence (spontaneous and hydrogen peroxide-induced) and state of lipid peroxidation were studied in 58 patients with erysipelas without diabetes mellitus (group I) and 46 patients with clinically manifest decompensated DM, predominantly type II one (group II), to get more specific information about their role in the pathogenesis of erysipelas presenting with concurrent DM. Group II patients showed more significant increase in measures of lipid peroxidation and degree of chemiluminescence, that did not reverse by the time a patient was discharged from the hospital, which fact is to be considered in instituting therapeutic and rehabilitative measures in those patients with erysipelas concurrent with DM.