Blood irradiation therapy is a procedure in which the blood is exposed to light (often laser light) for therapeutic reasons. Most research on blood irradiation therapy has been conducted in Russia and China[1] and it is rarely used outside of those countries. Its effectiveness and utility as a treatment has been questioned. Blood irradiation therapy can be administered through a catheter in a vein, through the blood vessels inside the nose or applied externally through the skin. It is not related to the practice of gamma irradiation of blood in transfusion medicine.