Oxidative stress injury and apoptosis are the main mechanisms of myocardial ischemia-reperfusion injury (MI/RI). Compounds with anti-oxidant properties can treat MI/RI. Therefore, identification of natural antioxidants such as herbs or botanical drugs is an ideal strategy to develop safe and effective anti-MI/RI drugs. Cardioprotective effects of Ginseng are well documented and are attributable to its anti-oxidant, anti-inflammatory, anti-tumorigenic, anti-arrhythmic, anti-ischemic properties. Ginseng monomer 20®-dammarane -3 beta,6 alpha,12 beta,20,25-pentol(25-hydroxyl-Protopanaxatriol,25-OH-PPT), a novel compound, which belongs to panaxatriol category, is extracted from the leaves and stem of ginseng. It was first investigated for its anti-tumorigenic properties. In this study, we explored whether 25-OH-PTT plays a role in antioxidant stress injury and anti-apoptosis in cardiomyocytes. We also explored the mechanisms in order to provide a theoretical basis to develop 25-OH-PPT as a new drug for treatment of MI/RI. First, we used H₂O₂ to induce H9c2 cardiomyocytes in vitro resulting in an oxidative stress injury model and pretreated with 25-OH-PPT. Secondly, we examined the viability of H9c2 cells by MTT assay, the reactive oxygen species (ROS) content and mitochondrial membrane potential by flow cytometry as well as cell apoptosis by flow cytometry Annexin-FITC/PI and Hoechst 33258 staining. Furthermore, we pretreated H9c2 cells with PI3K inhibitor, LY294002, and observed the above phenomenon. Lastly, we examined the expressions of proteins related to the PI3K/Akt signaling pathway and the apoptotic proteins. We found that 25-OH-PPT can protect H9c2 cells against H₂O₂-induced injury, decrease apoptosis of H9c2 cells and ROS generation, and increase the mitochondrial membrane potential. It can also upregulate the protein expressions of p-Akt, p-eNOS, and Bcl-2 and down-regulate apoptotic proteins Bax and Caspase-3. Our results indicate that 25-OH-PPT inhibits H₂O₂-induced H9c2 cardiomyocytes injury through PI3K/Akt pathway. It may become a potential safe and effective traditional Chinese medicine monomer for treatment of MI/RI.