OBJECTIVE： To study the protective effect of Mongolian medicine Roudoukou-8 powder on cardiac tissue of experimental animals. METHODS： Using Compound danshen dripping pill as positive control （0.10 g/kg）， the experimental animals were given low-dose， medium-dose and high-dose of Roudoukou-8 powder （0.75， 1.50， 3.00 g/kg） intragastrically for 10 d once a day， and respiratory oxygen consumption method was used to investigate its effects on survival time of normal mice and isoproterenol hydrochloride-induced acute myocardial ischemia and hypoxia model mice. Using Compound danshen dripping pills as positive control （0.04 g/kg）， the experimental animals were given low-dose， medium-dose and high-dose of Roudoukou-8 powder （0.28， 0.56， 1.12 g/kg） intragastrically for 10 d once a day， and its effects on arrhythmia latency and arrhythmia duration of chloroform-epinephrine induced arrhythmia model rabbits was investigated as well as its effects on T wave amplitude， S-T amplitude and serum endogenous substance （LDH， SOD， MDA， CK） levels of cardiac tissue in pituitrin-induced acute myocardial injury model rabbits. The corresponding blank control and model control were provided in all experiments. RESULTS： Compound danshen dripping pill， medium-dose and high-dose of Roudoukou-8 powder could significantly prolong survival time of normal mice， acute myocardial ischemia and hypoxia model mice （P＜0.05 or P＜0.01）. Compound danshen dripping pill and high-dose of Roudoukou-8 powder could significantly prolong arrhythmia latency of rabbits （P＜0.05）， and also significantly shortened arrhythmia duration （P＜0.05）. Compound danshen dripping pill and medium-dose of Roudoukou-8 powder could significantly decrease the increase of ΣT wave amplitude in cardiac tissue of acute myocardial injury model rabbits （P＜0.05 or P＜0.01）. Compound danshen dripping pill， medium-dose and high-dose of Roudoukou-8 powder could significantly decrease the increase of  ΣT wave amplitudein cardiac tissue of acute myocardial ischemia model rabbits （P＜0.05 or P＜0.01）. Compound danshen dripping pill， low-dose and high-dose of Roudoukou-8 powder could significantly decrease the serum level of LDH in acute myocardial ischemia model rabbits （P＜0.05）. Medium-dose and high-dose of Roudoukou-8 powder could significantly decrease the serum levels of MDA and CK in acute myocardial ischemia model rabbits （P＜0.05）. Medium-dose and high-dose of Roudoukou-8 powder could significantly increase the serum levels of SOD in rabbits （P＜0.05）. CONCLUSIONS： Mongolian medicine Roudoukou-8 powder can improve the myocardial oxygen supply， protect the injured cardiomyocytes， prolong the arrhythmia latency and shorten the duration of arrhythmia in experimental animals， and have a protective effect on the heart of experimental animals.