AIM To study the effects and mechanism of Diaoxinxuekang on hydrogen peroxide (H2O2) injured cardiomyocytes with a serum pharmacological method.METHODS Prepared the serum containing Diaoxinxuekang (600 mg· kg-1) with serum pharmacological method.Cardiomyocytes derived from neonatal rats were cultured in Dulbecco Modified Eagle Medium (DMEM).The cardiomyocytes were injured with hydrogen peroxide (H2O2), and treated with the serum containing different concerutration of Diaoxinxuekang.The survival rates of cardiomyocytes was measured with MTT method.The content of malondialdehyde (MDA) and lactate dehydrogenase(LDH), and the activity of total superexide dismutase (T-SOD) and catalase(CAT) were measured.RESULTS The survival rates of cardiomyocytes injured with H2O2 for 2 h were decreased significantly compared with normal cells (P <0.01).The content of MDA and LDH were increased significantly, but the activity of T-SOD and CAT were decreased.After treated with the different concentrations of drug-containing serum, the survival rate were increased with a dose-dependant manner (P < 0.01).The content of MDA and LDH were decreased and the activity of SOD and CAT were significantly increased (P < 0.01).CONCLUSION Diaoxinxuekang can protect the H202 injured cardiomyocytes by increasing antioxidafion capability.