||This article needs more medical references for verification or relies too heavily on primary sources. (November 2012)|
||The neutrality of this article is disputed. (December 2011)|
Ozone therapy is a form of alternative medicine treatment that purports to increase the amount of oxygen to the body through the introduction of ozone into the body. Various methods have been suggested on the method of introducing the ozone into the body, and the purported benefits of this therapy include the treatment of various diseases including cancer, AIDS, multiple sclerosis, among others. The American Cancer Society has concluded there is no evidence to support the use of this treatment in any disease.
Historical uses 
In 1856, just 16 years after its discovery, ozone was first used in a health care setting to disinfect operating rooms and sterilize surgical instruments. By the end of the 19th century the use of ozone to disinfect drinking water of bacteria and viruses was well established in mainland Europe. In 1892 The Lancet published an article describing the administration of ozone for treatment of tuberculosis. Ozone was used during the First World War to disinfect wounds.
Proposed use and scientific evaluation 
Ozone therapy consists of the introduction of ozone into the body via various methods, usually involving mixing of the ozone with various gases and liquids and injecting this into the body, including the vagina, rectum, intramuscular (in a muscle) or subcutaneously (under the skin). Ozone can also be introduced via autohemotherapy, in which blood is drawn from the patient, exposed to ozone and re-injected into the patient.
This therapy has been proposed for use in various diseases, including cancer, AIDS, multiple sclerosis, arthritis, heart disease, Alzheimer's dementia, among others. One proposed mechanism for its use in treating cancer comes from the proposed theory that cancer does not thrive or grow in a high oxygen environment, and the ozone therapy will increase oxygen in the body and therefore help treat the cancer. There is no evidence to support this theory. For treatment of HIV/AIDS, although ozone deactivates the viral particles outside the body, there is no evidence of benefits to living patients.
Summarizing the substantial and growing body of study results showing deleterious health effects of breathing ozone, in 1976, and reiterated in 2006, the United States Food and Drug Administration (FDA) reflects the scientific consensus that ozone is a toxic gas which has, as yet, no demonstrated safe medical application in specific, adjunctive, or preventive therapy. One possible reason, noted by the FDA, is that in order for ozone to be effective as a germicide, it must be present in a concentration far greater than can be safely tolerated by man or other animals.
It is also noted that cinema projectionists who were exposed to excessive levels of ozone as a byproduct of the carbon arc lamps used in the projectors developed what was known as "Projectionists Lung". Ozone caused a deterioration of the lower lung membranes.
A 1999 review concluded that "In the age of molecular medicine it is a real ‘act of faith’ to believe that ozone therapy might be a valid therapeutic option."  A review article published in 2001 found that knowledge regarding the potential benefit and harm of ozone in cancer patients is insufficient. Therefore it did not recommend it as an alternative form of treatment for cancer patients.
There is some controversy about its use by athletes in an attempt to increase performance.
Much of the concern related to ozone therapy revolves around the safety of blood ozonation. It is well established that when inhaled by mammals, ozone reacts with compounds in tissues lining the lungs and triggers a cascade of pathological effects. Saul Green has argued that since ozone has the capacity to oxidize organic compounds in an atmospheric environment, it should also logically oxidize blood components and endogenous human tissues. When infused into human blood, ozone produces reactive oxygen species (ROS) or free radicals, an over-abundance of which is known to cause oxidative stress and cell damage, and is implicated in the progression of some degenerative diseases. High levels of inhaled ozone is known to be toxic, though single-dose inhalation of lower levels is not.
See also 
- "Oxygen Therapy". American Cancer Society. Retrieved 29 November 2012.
- Chemical Technology Encyclopedia; Barnes & Noble 1968 vol 1 pp 82-3
- Suchkov BP (June 1964). "[Study of the Ozonization of Drinking Water Containing Pathogenic Bacteria and Viruses]". Gig Sanit (in Russian) 29: 22–9. PMID 14235449.
- "The Internal Administration of Ozone in the Treatment of Phthisis". Lancet II: 1180–1181. 1892.
- Stoker, George (1916). "The Surgical Uses of Ozone". Lancet II: 712.
- Green, S (1997). "Oxygenation Therapy: Unproven Treatments for Cancer and AIDS". Scientific Review of Alternative Medicine.
- "Code of Federal Regulations, Title 21 Vol 8 section 801.415". United States Food & Drug Administration. 2011-04-01. Retrieved 2011-10-04.
- "Health Effects of Ozone in the General Population". US Environmental Protection Agency. Retrieved 2012-11-17.
- Bocci, V (1999). "Biological and clinical effects of ozone. Has ozone therapy a future in medicine?". British journal of biomedical science 56 (4): 270–9. PMID 10795372.
- Ernst E (January 2001). "A primer of complementary and alternative medicine commonly used by cancer patients". Med. J. Aust. 174 (2): 88–92. PMID 11245510.
- Azarpazhooh, A.; Limeback, H. (2008). "The application of ozone in dentistry: A systematic review of literature". Journal of Dentistry 36 (2): 104–116. doi:10.1016/j.jdent.2007.11.008. PMID 18166260.
- Steppan J, Meaders T, Muto M, Murphy KJ (April 2010). "A metaanalysis of the effectiveness and safety of ozone treatments for herniated lumbar discs". J Vasc Interv Radiol 21 (4): 534–48. doi:10.1016/j.jvir.2009.12.393. PMID 20188591.
- "Belgian Court Continuing Investigation Of Ozone-therapy Doctor". Cyclingnews.com. Retrieved 2013-02-10.
- "Oxygenation therapy: Unproven treatments for Cancer and AIDS". Scientific Review of Alternative Medicine 1997.
- Bocci V, Valacchi G, Corradeschi F et al. (1998). "Studies on the biological effects of ozone: 7. Generation of reactive oxygen species (ROS) after exposure of human blood to ozone". J. Biol. Regul. Homeost. Agents 12 (3): 67–75. PMID 9795834.
- Bocci, V.; Borrelli, E.; Travagli, V.; Zanardi, I. (2009). "The ozone paradox: Ozone is a strong oxidant as well as a medical drug". Medicinal Research Reviews 29 (4): 646–682. doi:10.1002/med.20150. PMID 19260079.