Abstract: The purpose of this study was to evaluate protective effects of vitamin E, selenium and propranolol on TCDD induced changes of biochemical parameters using the rat liver perfusion system. Various concentrations of TCDD (0.3, 3, 20, 30 μg L-1) were added to the perfusion fluid and biochemical changes in perfusion fluid of isolated rat liver were examined within 2 h. The results showed that TCDD significantly increases the aminotransferase activities in a dose-dependent manner. It was determined that TCDD at 20 μg L-1 caused a maximum increase in biochemical parameters within 2 h (p<0.0001). The result also showed that propranolol (20 mg L-1), sodium selenite (345 mg L-1) and vitamin E (α-tocopherol, 700 mg L-1) significantly decreases TCDD hepatotoxicity. Aminotransferase enzyme activity as well as glutathione and protein content significantly changed in treatment groups as compared to the TCDD group (p<0.001). Reduction in hepatotoxicity may be attributed to prevention of lipid peroxidation, although other mechanisms may also be involved.