Ozone therapy: what it is and what the evidence shows

What ozone therapy is

Ozone (O3) is a reactive form of oxygen. Ozone therapy uses a generator to make medical-grade ozone, with the stated goal of raising oxygen in the body. Supporters say it supports healing and immunity. Cleveland Clinic calls the practice controversial and unregulated.

Common ways it's given:

• Autohemotherapy: blood is drawn, mixed with ozone and returned through an IV.
• Insufflation: ozone gas blown into the rectum, vagina or ears.
• Injection: an oxygen and ozone mix injected into a muscle.
• On the skin: ozonated oils or water on wounds, or an enclosed "ozone sauna."
• By mouth: ozone dissolved in oil or water.

How integrative practitioners use it

Cleveland Clinic calls ozone an alternative therapy, and researchers study it as an integrative treatment. People seek it out hoping for pain relief, wound healing and immune support. A 2023 evidence map of ozone as integrative medicine found the research centers on pain, infections, inflammation and wound healing.

What a session can look like depends on the route:

• Injection: most studies use an oxygen and ozone gas mix injected into a joint, a spinal disc, the muscles beside the spine or another muscle. How often and how much varies widely between clinics and studies.
• Autohemotherapy: ozone is dissolved in a sample of your blood, which is then returned to you through an IV.
• Rectal insufflation or an ozone sauna: gas is blown into the rectum, or a section of the body sits under a protective covering filled with ozone.

Doses and protocols vary widely from study to study, which is one reason results are hard to compare. These are descriptions of how it's given, not a promise of results.

What the research shows so far

Ozone has been studied for COPD, diabetes, fibromyalgia, HIV, cancer, disk herniation and carpal tunnel syndrome. Cleveland Clinic describes the evidence for claimed benefits, such as immune support, circulation and antimicrobial effects, as limited and low quality. It hasn't been tested in large human clinical trials, and experts say its dosing still needs to be standardized.

The 2023 evidence map found 26 systematic reviews. Its authors rated about half of them low or critically low quality and noted that many were held back by differences between studies and poor-quality underlying studies. The reviews it mapped linked no serious side effects to ozone, and mild ones came mainly with the injected gas mix. That doesn't rule out the rare, serious risks below.

In plain terms: the research is early, with limited studies of mixed quality, and ozone hasn't been shown in large trials yet to help any specific condition.

FDA's position on ozone

FDA's regulation on ozone-generating devices, 21 CFR 801.415, opens by stating that ozone is a toxic gas with no known useful medical application in specific, adjunctive, or preventive therapy. It says ozone strong enough to kill germs is far more than people can safely tolerate.

Under that rule, an ozone device is considered adulterated or misbranded if it's used for any medical condition without proof of safety and effectiveness, if it releases ozone where sick people are housed, or if it puts out ozone above 0.05 parts per million or lets ozone build up above that level in rooms where people spend long periods.

FDA also acts against ozone blood devices. In July 2025 it sent a warning letter to a company selling ozone and UV blood treatment devices marketed for autoimmune, heart and lung diseases, finding the devices adulterated because they lacked FDA premarket approval.

Risks and side effects

• Air embolism: gas bubbles from IV ozone can block a blood vessel and may cause a stroke or heart attack.
• Lung damage if inhaled: even low levels can cause burning eyes, cough, chest pain, shortness of breath and headache. Over time it can injure the lungs and worsen asthma or COPD. Ozone should never be inhaled.
• Delayed harm: FDA's rule notes lung swelling from ozone can appear hours after exposure, so feeling fine isn't a reliable sign of safety.
• Cramping and discomfort after rectal insufflation, and flu-like reactions after treatment.

Don't try ozone at home, and be cautious with any provider who offers it in place of standard care for cancer, infections or chronic disease. Talk with your clinician first, especially if you have asthma, COPD or another lung condition, which ozone can worsen.

Call 911 for chest pain, sudden shortness of breath, weakness or numbness on one side, trouble speaking, or confusion during or after an ozone treatment.

Your call, with a good practitioner

Whether to try ozone is your decision. A good practitioner will answer these plainly:

• What exactly is being given, by which route, and what is the evidence in people for my condition?
• Who is the licensed clinician responsible, and what training do they have?
• What happens if there's an emergency during treatment?
• Does this interact with my medications or conditions, and does my own clinician agree?
• What does the full course cost?

Red flags: a provider who has you breathe ozone, sells a home generator for medical use, offers ozone in place of standard care for a serious illness, can't name the licensed clinician responsible, or has no emergency plan.

Gabriel can find and book a qualified practitioner or clinic for you. Read about ozone sessions, or ask Gabriel free to talk through the evidence before you decide.