Fruits of Arctium lappa L. (Compositae), which has been used as the antiinflammatory, detoxifying and diuretic agents in the folk remedies, was examined on the in vitro oxidation of human low density lipoprotein (LDL). Several lines of evidence indicate that oxidized LDL (Ox-LDL) may promote atherogenesis. Hence. The role of antioxidants in the prevention of LDL oxidation needs to be determined. The activity of fractions of Arctii Fructus treated with oxidized LDL which was incubated with $16;{mu}M$ of $Cu^{2+}$ for metal catalyzed oxidation was investigated. The BuOH fraction (4;ppm) inhibited the oxidative modification of LDL as evidenced by a decrease in the lipid peroxide content (thiobarbituric acid reacting substances activity), the negative charge of LDL (electrophoretic mobility) and increase of the vitamine E content.