The effect of Compound Danshen injection (CDI) on anesthetized dog models of myocardial ischemia was investigated. The dog models were established by ligation of main branch of left coronary artery. The results showed that CDI reduced the release of serum CK,LDH and MDA and increased the activity of SOD, decreased the scope of myocardial infarction and slowed down the quickened heart beat induced by ischemia. The differences were significant as compared with those in the model group (P