Blood irradiation therapy is an alternative medical procedure in which the blood is exposed to low level light (often laser light) for therapeutic reasons. The practice was originally developed in the United States, but most recent research on it has been conducted in Germany (by UV lamps) and in Russia (in all variants). Low-level laser therapy has been tested for a wide range of conditions, but rigorous double-blinded studies have not yet been performed. Furthermore, it has been claimed that ultraviolet irradiation of blood kills bacteria by DNA damage and also activation of the immune system. Blood irradiation therapy is highly controversial, and has fallen from mainstream use since its heyday in the 1940s and 1950s. Blood irradiation therapy can be administered in three ways: extracorporeally, transcutaneously, and intravenously. The extracorporeal (outside the body) method removes blood from the body and irradiates it in a special cuvette (tube). This method is used for the ultraviolet (UV) blood irradiation (UVBI) by UV lamps. In the transcutaneous method, the radiation goes through the skin, by placing a device on the outside of the skin. In the intravenous method, a device is inserted into a large blood vessel. The laser light is monochromatic. It is not related to the practice of gamma irradiation of blood in transfusion medicine. History In 1928, Dr. Emmet Knott and a medical student named Lester Edblom received a United States patent for a "Means for Treating Blood-Stream Infection" that incorporated a rudimentary ultraviolet bulb, vacuum extraction system and a cuvette. The "Knott Hemo-Irradiator" was used from the 1930s through the 1950s on patients with multiple infectious diseases. George P Miley at the Hahnemann Hospital in Philadelphia, Pennsylvania, published a series of articles on the use of the procedure in the treatment of thrombophlebitis, staphylococcal sepsis, peritonitis, botulism, poliomyelitis, non-healing wounds, and asthma. One of the best known and most comprehensive set of studies was published in 1947 by Dr. George Miley and Dr. Jens A Christensen (from the Blood Irradiation Clinic of the Hahnemann Medical College and Hospital of Philadelphia, Pennsylvania). The authors studied 445 cases of acute pyogenic infections and 74 cases of virus and virus-like infections. Findings included the following: sulfonamide-resistant and penicillin-resistant infections have responded to the treatment. Further finding included: "We have observed that toxemias due to various virus and virus-like infections subside rapidly …” Some of the more impressive results included cases involving