The paper shows, that patients with purulent meningitis on the background of severe clinical and laboratory changes had a disturbance of prooxidant-antioxidant regulation with a shift towards activation of free radical oxidation. In the dynamics of the disease, after 7-10 days of conventional treatment, against the background of a reduction of cephalic and meningeal syndromes intensity, a normalization of liquor and hemogram indices, in most patients there was a further decrease in catalase activity and an increase of nitrites, of parameters of spontaneous and induced oxidative modification of blood proteins that remained when the patients were discharged, compared with healthy people.