The invention relates to salvinorin compositions and uses thereof. Specifically, the invention relates to administering salvinorin compositions to treat diseases and disorders associated with vasoconstriction, vaso-occlusion, or disruption of blood flow and autoregulation. For example, salvinorin compositions may be administered to subjects with cardiac arrest, subarachnoid hemorrhage, stroke, cerebral vascular spasm, cerebral hypoxia/ischemia, cerebral artery occlusion, or any condition involved in autoregulation impairment.