Lipid peroxidation products measured as a malondialdehyde and activities of superoxide dism utase (SOD), glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), and concentrations of ascorbic acid,-tocopherol, and glutathione (GSH) were measured in the liver, erythrocytes, and serum of rats 6, 14, and 24 h and 2, 5, and 7 d after treatment with 3 g methanol/ kg. GSH-Px and GSSG-R activities, GSH level, and ascorbate concentration in the liver, erythrocytes, and blood serum were significantly decreased. In addition, SOD and-tocopherol in erythrocytes were diminished, while malondialdehyde (MDA) in liver, erythrocytes, and serum were elevated. Further, erythrocyte counts, hemoglobin levels, hematocrit, and mean corpuscular volume (MCV) were reduced. These results indicate that methanol intoxication in rats leads to an increase in the lipid peroxidation and impairment in the antioxidant mechanisms in liver, erythrocytes, and blood serum.