Objective To explore the protecting effect of Zuomu’ a Decoction（ 佐 木 阿 汤） on hypoxia injury of H9 C2 myocardial cells and the possible mechanism. Methods Fifty rats were randomized into the Zuomu’ a Decoction group [20 ml /（ kg· d）]（ n = 30）

the enalapril group（ n = 10） and the normal saline group [10 ml /（ kg ·d）]（ n = 10）. Rats in each group were given intragastric administration for 1 week. Then rats’ blood was taken from abdominal aorta to prepare drug containing serum. H9 C2 myocardial cell lines cultured were divided into the normal group

the model group

the normal saline group

the enalapril group

the Zuomu’ a Decoction 5 %

10 % and 15 %group. After drug containing serum intervention and hypoxia model establishment

cell viability and survival rate in each group were examined. The release of creatine kinase（ CK） and lactate dehydrogenase（ LDH）

as well as the activity of superoxide dismutase（ SOD） and malonyldialdehyde（ MDA） were detected. Results Compared with the normal group

cell viability and survival rate in the model group and the normal saline serum group decreased.The release of CK and LDH increased. The activity of MDA increased

while the activity of SOD decreased（ P <0. 05）. Compared with the model group

cell viability in the Zuomu’ a Decoction 5 %

10 % and 15 % group and the enalapril group increased

while the release of CK and LDH decreased（ P < 0. 05）. Cell survival rate and the activity of SOD in the Zuomu’ a Decoction15 % serum group were higher than those in the model group and the normal saline group. The release of CK and LDH

as well as the activity of MDA decreased（ P < 0. 05）. Conclusion Zuomu’ a Decoction might relieve the hypoxia injury of myocardial cells. The mechanism might relate to reducing the release of myocardial cell membrane CK and LDH

increasing myocardial SOD activity and reducing MDA activity.