The aim of this paper was to define the influence of long-term methanol intoxication on the changes of end products of lipid peroxidation, reacting with thiobarbituric acid (TBA-reactive products) and free SH-group concentration in rat brains. The experiment was conducted on male Lewis rats. The experimental groups received a 1-molar methanol solution and the control group received tap water. The animals were killed after 4, 8 and 12 weeks of intoxication and their brains were collected for further examination, which encompassed measurement of the concentration of TBA-reactive products and free SH-groups. The revealed changes of TBA-reactive products and free SH-group concentration were not statistically significant.