Ozone therapy- 

Ozone is triatomic oxygen or O3 that has been used in medicine for decades, as a treatment for tuberculosis in 1892, as a surgical disinfectant, and more recently as a treatment administered to patients directly as an injection into the lumbar intervertebral disc or exiting nerve space, injection into joints, or by mixing with blood obtained from a patient followed by re-infusion back into the patient (autohemotherapy). It is a respiratory irritant and is toxic to the lungs, so breathing ozone as a medical treatment is not acceptable.  The FDA is so concerned about the proliferation of ozone usage in the US, they are attempting to regulate ozone generators (21CFR801.415).  There is scientific evidence to support its use as an injection into the disc, epidural space, muscles of the spine (Drug Des Devel Ther. 2015 May 15;9:2677-85,, Pain Physician. 2012 Mar-Apr;15(2):E115-29),  knee (J Orthop Surg Res. 2017 Jan 23;12(1):16).  There is some support for autohemotherapy in multiple sclerosis patients, gout, critical limb ischemia, as a means to prevent kidney reperfusion injury with surgery, dry macular degeneration, and preliminary results in the treatment of hepatitis C.