Sixteen dairy cows were studied to assess the status of the natural antioxidant vitamin E and lipid peroxidation in their livers. Cows with liver failure (n = 7) showed clinical signs of a hepatic encephalopathy and had the following values of selected blood indices: AST > 80 U/l and GLDH > 15 U/l in serum, and venous plasma ammonia > 35 mmol/l. The control group (n = 9) consisted of dairy cows which were recovering from surgery (omentopexy) and were free of any health complications. Blood was analysed for α‐tocopherol, aspartate aminotransferase, glutamate dehydrogenase, γ‐glutamyl transferase, total bilirubin, ammonia, cholesterol, albumin, free fatty acids, glucose, and β‐hydroxybutyrate. Alpha‐tocopherol, triglyceride and malondialdehyde were measured in wet liver tissue. The cows with hepatic failure were clearly low in α‐tocopherol and had significantly lower (P < 0.01) plasma α‐tocopherol than the controls. Both liver triglycerides and MDA were higher (P < 0.05) in the cows with fatty livers. It is concluded that the cows with liver failure had an increase in the intensity of hepatic lipoperoxidative processes and a low antioxidative status, which should be taken into consideration in cases where treatment of the disease is proposed.