Mugwort has been used as a Korean folk medicine in treating liver diseases acting as an analgesics, sedative, diuresis, choleretics. This study was perfomed to evaluate the effect of mugwort extracts on the changes of enzyme activities, lipid accumulation of the serum and liver, when hepatotoxicity was induced by benzo(a)pyrene. The results are as follows: 1. Mugwort water extract administration prevented the increase of serum and liver AST, ALT, LDH, ${gamma}$-GTP, liver ALP activities and bilirubin content caused by B(a)P injection. 2. The increase of serum and liver ALT, LDH, ${gamma}$-GTP, serum AST activities and liver bilirubin contents in B(a)P treated group were decreased by mugwort methanol extract treatment. 3. Serum and liver total cholesterol, phospholipid, triglyceride level and serum HDL-cholesterol level were increased by B(a)P treatment. After combined treatment of mugwort water and methanul extracts, these lipid content were significantly decreased. 4. The hepatotropic effect of mugwort water extract and after-treatment against B(a)P induced hepatotoxicity was superior to that of methanol extract and pretreatment.