A non-invasive method of treating cerebral ischemia, involving the use of non-inhaled, intra-nasally delivered carbon dioxide (CO2), alone or in combination with other gases to augment cerebral perfusion and improve outcome following a stroke is provided. A vasodilator gas is delivered intranasally, alone or in combination with a second gas, for prolonged periods of time without systemic absorption. The second gas may be selected from NO, hydrogen, xenon, anesthetic gases, oxygen, nitrogen, nitrous oxide, carbon monoxide, or air. The treatment selectively increases cerebral perfusion and provides neuroprotection in the treatment of cerebral ischemia.
