Objective:To investigate whether the administration of the ultra-filtration extract from Danggui Buxue Decoction(当归补血汤,EDBD) was able to protect cardiomyocytes from oxidative injury of rats induced by hydrogen peroxide(H_2O_2) and its potential mechanism.Methods:Myocardial cells from 1- to 2-day-old neonatal rats were cultured in Dulbecco’s modified Eagle’s medium low-glucose and Ham’s F12 medium(1:1),and the cellular injury was induced by H_2O_2.The ultra-filtration extract mixture from Angelica sinensis and Hedysarum polybotrys was given in three doses of 3.75,7.5,and 15 mg/mL.Morphological changes of cardiomyocytes were observed by microscope.Survival rate of myocardial cells was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay.The cardiomyocyte damages were estimated by detecting lactate dehydrogenase(LDH) and creatine kinase(CK) releases in the medium,superoxide dismutase(SOD) activities, and intracellular malondialdehyde(MDA) and myeloperoxidase(MPO) contents.The levels of caspase-3 and heat shock protein 70(hsp70) mRNA expression in cardiomyocytes were measured by reverse transcription polymerase chain reaction.Results:The EDBD could protect the cardiomyocytes from H_2O_2 injury in a dose-dependent manner(3.75,7.50,and 15.00 mg/mL).The EDBD could significantly decrease LDH and CK leakages and intracellular MDA and MPO contents,increase SOD activity,up-regulate hsp70 expression,and down-regulate caspase-3 expression.Conclusion:The EDBD has protection on cardiomyocytes injured by H_2O_2 through improving cell antioxidant ability,up-regulating hsp70 expression,and inhibiting caspase-3 activity. Objective: To investigate whether the administration of the ultra-filtration extract from Danggui Buxue Decoction (EDBD) was able to protect cardiomyocytes from oxidative injury of rats induced by hydrogen peroxide (H_2O_2) and its potential mechanism. Methods: Myocardial cells from 1- to 2-day old neonatal rats were cultured in Dulbecco’s modified Eagle’s medium low-glucose and Ham’s F12 medium (1: 1), and the cellular injury was induced by H 2 O 2. The ultra-filtration extract mixture from Angelica sinensis and Morphival changes of cardiomyocytes were observed by microscope. Survival rate of myocardial cells was assessed using 3- (4,5-dimethylthiazol-2-yl) -2 , 5-diphenyltetrazolium bromide (MTT) assay. The cardiomyocyte damages were estimated by detecting lactate dehydrogenase (LDH) and creatine kinase (CK) releases in the medium, superoxide dismutase (SOD) activities, and intracellular malondialdehyde (MDA) and my Eloperoxidase (MPO) contents. These levels of caspase-3 and heat shock protein 70 (hsp70) mRNA expression in cardiomyocytes were measured by reverse transcription polymerase chain reaction. Results: The EDBD could protect the cardiomyocytes from H 2 O 2 injury in a dose-dependent manner (3.75, 7.50, and 15.00 mg / mL). The EDBD could not decrease LDH and CK leakages and intracellular MDA and MPO contents, increase SOD activity, up-regulate hsp70 expression, and down- regulate caspase- EDBD has protection on cardiomyocytes injured by H_2O_2 through improving cell antioxidant ability, up-regulating hsp70 expression, and inhibiting caspase-3 activity.