Objective To study the effect of liquid extracts from leaves of Canarium pimela Leenh on myo-cardial ischemia-reperfusion injury in rats. Methods The langendorff isolated perfused heart system was applied in this study. Ligating of the left descending anterior for 35 min,followed with 100 min or 50 min reperfusing to set up the cardiac ischemia-reperfusion injury model (I/R). After perfusing the effective pharmacological extracts of leaves of Canarium pimela Leenh(CPL)to the isolated heart,we monitored the cardiac parameters of left ventricu-lar systolic pressure(LVSP),left ventricular end-diastolic pressure(LVEDP)and left ventricular maximal rise/fall of left ventricular pressure(±dp/dtmax)in the following assays with or without 10 min CPL pretreatment. 1. the cardiac parameters,2. the cardiac parameters in 35 min ischemia,followed with 10 min or 50 min reperfusion,3. the incidence of ventricular fibrillation or ventricular tachycardia after 10 min reperfusion,4. the activity of creatine kinase(CK)and lactate dehydrogenase(LDH)in the coronary effluent after 10 min reperfusion,5. pathological analysis in the I/R,CPL and VER group after reperfusion. Results CPL pretreatment improved functions of normal left heart. Furthermore,it significantly reduced LVEDP and +dp/dtmax,the incidence of ventricular fibrillation or ventricular tachycardia,as well as the activities of CK and LDH in coronary effluent induced by ischemia-reperfusion compared with the I/R model. Moreover,CPL pretreatment markedly alleivated the pathological changes of ischemia-reperfusion. Conclusions The liquid extracts of leaves of Canarium pimela Leenh can effectively relieve the myocardial ischemia-reperfusion injury in rats.