The aim of the present study was to investigate the influence of tetrabromobenzene after 28 days administration on biochemical indicators. The increase in relative liver mass as well as changes in the levels of cytochromes P-450 were observed. Porphyrins excreted in urine does not indicate strong porphyrogenic effect. No statistically significant changes were detected in other indicators of toxicity (MDA, GSH, ALT, rGT).