The effect of glatiramer acetate on the structure of the lipid phase of cell membranes of red blood cells, the status of lipid peroxidation and antioxidant defense system in patients with relapsing forms of multiple sclerosis. It is shown that during treatment with glatiramer acetate reduces the initially high, level of phospholipase A2, and the concentration of lipid peroxidation products - diene conjugates and Schiff bases. At the same time against the increase initially reduced activity of the antioxidant defense normal structure of erythrocyte membranes in patients with relapsing-remitting multiple sclerosis. Based on the analysis of the dynamics of laboratory parameters proved membranoprotektiv effect the drug.