Activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px) and glutathione reductase (GSSG-R) and concentration of ascorbate, a-tocopherol, non-protein and protein-bound sulfhydryi compounds and thio- barbituric acid-reactive substances (TBA-rs) were measured in liver and serum of rats 6, 12 and 24 h and 2, 5 and 7 days after intoxication with 1.5 g or 3.0 g methanol/kg b.w. Liver GSH-Px and GSSG-R activities and SH-groups and ascorbate content were significantly diminished at 6 and 24 h, while TBA-rs were increased. Serum SOD, GSH-Px and GSSG-R activities and SH-groups concentration were reduced while TBA-rs were elevated. The changes were more intensive after application of the higher dose of methanol. It is concluded that methanol impairs the liver and blood serum antioxidant mechanisms in rats.