Comparative study on effect of refined Xuefu capsule, Xuefu Zhuyu capsule and diltiazem on mRNA expression of nitric oxide synthase (NOS) and release of LDH-L, CK, GOT of hypoxic hypoglycemic cultured myocytes were studied by using the serum pharmacological method, reverse transcriptase-polymerase chain reaction (RT-PCR) and Northen blotting. It was shown that the three drugs can reduce release of LDH-L,CK,GOT of myocytes (P < 0.01), the effect of refined Xuefu capsule and diltiazem were obvious than that of Xuefu Zhuyu capsule in reducing LDH-L release and NOS mRNA expression (P < 0.01), and effect of refined Xuefu capsule was the strongest (P < 0.01). These findings indicated that all 3 drugs have significant effect in protecting myocytes which related to their effect on NO production of myocyte particularly the refined Xuefu capsule and diltiazem.