The chronic experiments on mongrel dogs with a model pancreatitis showed that mexidol decreases manifestations of the inflammatory process. The treatment with mexidol led to a decrease in the degree of lipid transformations in the initial stage of pancreatitis development, with normaliation of the lipid metabolism according to the liver and blood plasma characteristics. The membranoprotector effect of mexidol, manifested in normalization of the lipid spectrum, is probably related to inhibition of the lipid peroxidation (LPO) process and to a decrease in the activity of phospholipase A2. The correlation between lipid metabolism, LPO, and phospholipase A2 activity in the tissues studied indicates that the therapeutic effect of mexidol in animals with pancreatitis is based on the cytoprotector activity of the drug.