This study is designed to investigate the effects of Samul-Tang extract on the response of lactic dehydrogenase(LDH) release, cellular activity, lipid peroxidation, DNA synthesis and the changes of total protein of bovine pulmonary artery endothelial cells(PAEC) from hydrogen peroxide$(H_2O_2)$-induced injury. The results are as follows : 1. Samul-Tang significantly decreased $H_2O_2$-induced release of LDH from injured bovine PAEC. 2. Samul-Tang significantly repressed $H_2O_2$-induced cellular activity from injured bovine PAEC. 3. Samul-Tang significantly repressed $H_2O_2$-induced lipid peroxidation from injured bovine PAEC. 4. Samul-Tang significantly stimulated DNA synthesis in bovine PAEC. 5. Samul-Tang significantly repressed $H_2O_2$-induced changes of total protein volume from injured bovine PAEC. Above results suggest that Samul-Tang can protect bovine PAEC from $H_2O_2$-induced injury. These results can be effectively applied to the prevention and cure of cardiovascular and cerebrovascular diseases.