OBJECTIVE: To study the effect of hesperidin and rutin on oxidative modification of high density lipoprotein (HDL) in vitro. METHODS: HDL was isolated from healthy human plasma by sequential ultracentrifugation, and was oxidized by copper ions. The inhibitory effects of hesperidin and rutin on HDL oxidative modification were valued by the formation of malondialdehyde (MDA). RESULTS: Hesperidin and rutin significantly inhibited copper-induced oxidation of HDL in a dose-dependent manner. CONCLUSION: Both hesperidin and rutin can prevent HDL from copper-induced oxidative modification in vitro. This result suggests that they might have antiatherogenic effect.