The present invention relates to a composition for preventing, treating, or alleviating ischemia-reperfusion injury, containing bile acid. According to the present invention, bile acid increases intranuclear beta-catenin levels, interferes with the opening of a mitochondria permeable transition pore (mPTP), and has excellent effects, in ischemia-reperfusion injury animal models, of alleviating tissue injury and reducing the size of infarcts, thereby being usable in the prevention, treatment, or alleviation of ischemia-reperfusion injury.