In this study, we aimed to investigate the effects of vitamin U (Vit U) on valproic acid (VPA)-induced liver damage. Female Sprague Dawley rats were randomly divided into four groups. Group I was intact control animals. Group If was control rats given Vit U (50 mg/kg/day) for fifteen days. Group III was given only VPA (500 mg/kg/day) for fifteen days. Group IV was given VPA + Vit U (in same dose and time). Vit U was given to rats by gavage and VPA was given intraperitoneally. On the 16th day of experiment, all the animals were fasted overnight and then sacrificed under ether anesthesia. Liver tissue was taken from animals, homogenized in 0.9% saline to make up to 10% homogenate. Liver aspartate and alanine transaminases, alkaline phosphatase, lactate dehydrogenase, myeloperoxidase, sorbitol dehydrogenase, glutamate dehydrogenase and xanthine oxidase activities and lipid peroxidation levels were increased and paraoxonase activity and glutathione levels were decreased in VPA group. Treatment with Vit U reversed these effects. These results demonstrated that administration of Vit U is a potentially beneficial agent to reduce the liver damage in VPA induced hepatotoxicity, probably by decreasing oxidative stress. (C) 2012 Elsevier Ltd. All rights reserved.