Objective. To study the efficacy of cytoflavin in correction of oxidative stress and the activity of Na/K-ATPase in posttraumatic craniocerebral trauma (CCT) in rats. Material and methods. The study was performed on white non-linear female rats with a modeled CCT. An effect of cytoflavin on free radical oxidation and plasma antioxidant system, processes of plasma lipid peroxidation and antioxidant properties of red blood cells and erythrocyte Na/KATPases activity was studied on 1, 3, 7- and 12th day after CCT. Results and conclusion. CCT identified the growth of free-radical processes in blood plasma and an increase in lipid peroxidation in plasma and red blood cells as well as a reduction in the activity of catalase and Na/K-ATPase. Introduction of cytoflavin reduced oxidative stress from the 3rd day and normalized free radical oxidation and lipid peroxidation in plasma and red blood cells to the 7th day of the study against the background of the high total antioxidant capacity of blood and erythrocyte catalase activity. The effect of cytoflavin led to an increase in the activity of Na/K-ATPase on the 3rd—7th day of the study compared with the reduced activity of the enzyme in the control. Recovery of pro- and antioxidant balance under the action of cytoflavin associated with increased activity of Na/K-ATPase aimed at optimizing and reducing the homeostatic mechanisms of secondary damage in the post traumatic period.