Changes in the level of lipids peroxidation and activity of the antioxidation system in tissues of the stomach, brain and blood serum were studied in dynamics in experiments on rats on the first, fifth and tenth day of modeling of an ulcer process in the gastroduodenal region.

Disturbances in free-radical processes in all the studied tissues with maximal changes on the fifth experimental day were determined.

The revealed biochemical disturbances in tissues and blood correlated with morphological changes in the mucous membrane of the gastroduodenal region.