Inhibition of protein oxidation and DNA damage by reactive oxygen species (ROS) would confer benefit to living organisms exposed to oxidative stress, because oxidized proteins are associated with many diseases and can propagate ROS-induced damage. In this study, the ability of the ethanol extracts of Hypericum retusum Aucher (HR) and Hypericum scabrum L (HSm) to protect bovine serum albumin (BSA) from oxidation and DNA damage by hydroxyl radical derived from the Fenton system (Fe3+/H2O2/ascorbic acid) were measured. The ethanol extracts of HR and HSm at different concentrations (50-1000 g/mL) efficiently prevented protein oxidation induced by hydroxyl radicals as assayed by protein oxidation markers, including protein carbonyl formation (PCO) and polyacrylamide gel electrophoresis. The effect of ethanol extracts of HR and HSm on DNA cleavage induced by UV-photholysis of H2O2 using pBluescript M13+ plasmid DNA were also investigated. These extracts significantly inhibited DNA damage induced by ROS. Therefore, Hypericum retusum, and Hypericum scabrum extracts may be useful in the food industry as effective synthetic antioxidants.