Effects of Houttuynia cordata on the level of lipid peroxide and the enzyme activities of the liver were investigated in bromobenzene-induced rats. Lipid peroxide content in liver was increased by bromobenzene. It was decreased when the methanol extract from the aerial parts of H. cordata was treated to the rat. The methanol extract reduced the activities of aminopyrine N-demethylase and aniline hydroxylase that increased by bromobenzene, however did not affect glutathione S-transferase activity. The methanol extract recovered the activity of epoxide hydrolase activity that decreased significantly by bromobenzene. We suggest that under our experimental conditions the extract might play an important play in the prevention of hepatotoxicity by reduction of aminopyrine N-demethylase and aniline hydroxylase activities as well as enhancement of epoxide hydrolase activity. Six phenolic compounds have been isolated from H. cordata and identified by means of spectral analysis as protocatechuic acid, quercetin, apigenin, afzelin, hyperoside and quercitrin.