H2O2 and hydroxyl free radical active oxygen generation systems were utilized to define the antioxidant activities of simple phenolic compounds derived from Chinese herbs. Although the antioxidant activities of compounds differed when assessed in the two systems, all compounds tested were found to be effective at preventing red blood cell membrane lipid peroxidation, with the propyl and butyl esters of gallic acid being especially potent. No compound was able to prevent hemoglobin oxidation. All compounds but salicylic acid were found to interact dose-dependently with H2O2 and hydroxyl free radical as determined by a chemiluminescence method.