Viscum species have been widely used in herbal medicine, such as nervine, hypertensive, cardiac depressant, vasodilator, slowing and steadying of excessive heart rate, relaxant and diuretic. The genus Viscum L. (Loranthaceae) comprises semi-parasitic plants which grow on various host tree and shrubs In Turkey, Viscum L. is represented by one species (Viscum album L.) and three subspecies; namely ssp. album, ssp. abietis (Wiesb.) Abromeit and ssp. austriacum (Wiesb.) Vollmann and is known with a common name as ‘Ökse Otu’. In the present study, the effect of Viscum album ssp. album L. extract on partially hepatectomized rats was investigated with biochemical assay. The extracts of the plant at the concentrations of 1 and 1.5 ml/100 g body weight/day were administered orally to the two experimental groups including partially hepatectomized rats for 14 days. At the end of the experimental period, animals were sacrificed, blood was collected for the assessment of serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and blood urea nitrogen (BUN). Viscum album ssp. album extract given to the hepatectomized rats significantly increased the serum AST and ALT levels when compared to controls at the end of treatment. The increased ALT and AST levels in the serum suggest the possible hepatotoxic effects of extracts. However, AST and ALT levels at the concentration of 1 % were less than those of the levels of 1.5 %. This effect appeared to be dose dependent. On the other hand, we found significant decrease in the level of BUN. This result indicates kidney damage. Thus, it might be due to decreased utilization of urea by damaged liver.