Inhalation of hydrogen (H(2)) gas has been demonstrated to limit the infarct volume of brain and liver by reducing ischemia-reperfusion injury in rodents. When translated into clinical practice, this therapy must be most frequently applied in the treatment of patients with acute myocardial infarction, since angioplastic recanalization of infarct-related occluded coronary artery is routinely performed. Therefore, we investigate whether H(2) gas confers cardioprotection against ischemia-reperfusion injury in rats. In isolated perfused hearts, H(2) gas enhances the recovery of left ventricular function following anoxia-reoxygenation. Inhaled H(2) gas is rapidly transported and can reach 'at risk' ischemic myocardium before coronary blood flow of the occluded infarct-related artery is reestablished. Inhalation of H(2) gas at incombustible levels during ischemia and reperfusion reduces infarct size without altering hemodynamic parameters, thereby preventing deleterious left ventricular remodeling. Thus, inhalation of H(2) gas is promising strategy to alleviate ischemia-reperfusion injury coincident with recanalization of coronary artery.