Oxygen is necessary for life. You may fast from food; even go without water for a while, but you can’t live without oxygen for more than a few minutes. Oxygen plays a key role in every cellular process. It supports the immune system, neutralizes toxic substances, fuels metabolism, and promotes new cell growth.

There is a new craze on the rise for administering oxygen in proportions in excess of that found in normal atmospheric air, which contains only 21% oxygen (air contains 78% nitrogen). But how much extra oxygen is your body able to use?

In the airports of large cities throughout the world, oxygen bars are popping up where, for about a dollar a minute, you can inhale 100% pure oxygen, or even scented oxygen, with the hope that this will revitalize you. Professional athletes inhale oxygen before competition, eager to boost energy levels. Oxygen has become the trendy staple at day spas and health resorts, where the range of treatments now include oxygen pills, oxygen-enhanced drinks, and oxygenated skin creams. Oxygen promoters claim that regular shots of oxygen not only increase energy, but can also relieve all kinds of difficulties, from allergies to hangovers. Of course, medical practitioners have used oxygen in the medical field for a long time, but in this setting, practitioners administer it with careful controls to avoid possible complications from excessive use.

Although increasing oxygen intake seems harmless enough, there is little scientific evidence to substantiate recent beneficial claims and to set safety protocols beyond those already established in modern medicine. In fact, some physicians warn against the dangers of oxygen toxicity and possible cellular abnormalities from the overuse of oxygen therapy.

Other dangerous applications of modified oxygen are being touted as therapeutic when, in fact, they could be life threatening. There is only one form of oxygen therapy with clinical evidence supporting its use in the healing process, and that is Hyperbaric Oxygen Therapy (HBO2T).

Let’s first look at some of the applications that are not good for you:


Ozone Therapy (Not Recommended)

Ozone (O3) is a molecule of oxygen (O2) with an extra atom attached. Proponents of ozone therapy claim that the extra atom assures higher oxygen levels in the blood and tissues after normal oxidation begins stripping the atoms away.

Ozone, in the upper layer of the atmosphere (stratosphere), absorbs certain forms of radiation, protecting us from the harmful effects of the sun’s ultraviolet radiation. In the lower atmosphere where we live, breathing ozone even in small amounts can irritate the eyes, cause headaches, sore throats and coughs, aggravate other respiratory maladies, and damage the lungs. It can be fatal when inhaled directly in higher concentration. Health Canada warns against the use of ozone generators.

Hypothetically “therapeutic” use of ozone can only be administered in ways that avoid inhalation. Among the more common are by:

  • drinking water instilled with the gas, or
  • applying a mixture of olive oil and ozone directly to the skin, or
  • a process where blood is withdrawn from the body, mixed with ozone, and injected back into a vein (known as major autohemotherapy) or a muscle (known as minor autohemotherapy), or
  • blowing the gas into a body cavity such as the vagina, rectum, or ear drum (known as insufflation), or
  • circulating the gas around a limb that has been wrapped in a bag (known as limb-bagging).

When administered by injection, O3 can cause a number of problems including vein inflammation (phlebitis), poor circulation, chest pain, shortness of breath, fainting, coughing, flushing, heart irregularities, or dangerous bubbles in the bloodstream (embolism). When given rectally, it can inflame the lower intestinal tract. It is also highly irritating and drying to vaginal membranes.


Hydrogen Peroxide Therapy (Not Recommended)

Most people know hydrogen peroxide as the liquid you buy at the drug store for disinfecting scrapes and cuts. It forms when ozone (O3) interacts with water: the extra oxygen atom attached to the ozone molecule breaks off and combines with a water molecule (H2O) to create hydrogen peroxide (H2O2). It exists naturally in small quantities in the atmosphere, in raw fruits and vegetables, even in mother’s milk.

Commercial production of hydrogen peroxide is in different strengths or grades for different purposes. For example, the liquid at the drug store is 3% hydrogen peroxide. Manufacturers use a solution of 30% hydrogen peroxide to wash transistors before assembly. Food producers wash eggs and some kinds of cheese and whey products in 35% food-grade hydrogen peroxide. Manufacturers also use this substance to kill microorganisms in food storage products such as aluminum foil. At a 90% concentration, hydrogen peroxide is rocket fuel!

Advocates of hydrogen peroxide therapy usually recommend using food-grade, 35% hydrogen peroxide, which you can purchase online or in some health food stores. They advise bathing in a diluted solution, gargling with it, spraying it over the body, or soaking injured body parts in it. It is very important to know that hydrogen peroxide should not to be used internally. Never drink it or allow it entry rectally or vaginally; it can cause nausea and vomiting, and inflame the intestinal tract or vagina. If you are allergic or sensitive to this compound, you should also avoid external contact.

WHMIS classifies hydrogen peroxide as Class C-Oxidizing, Class E-Corrosive and Class F-Dangerously Reactive material. When given by injection, may cause fainting, fatigue, headaches, and chest pain. Still, some unethical practitioners inject the diluted solution directly into the bloodstream!

According to Health Canada, hydrogen peroxide >35% can cause irritation of the upper gastrointestinal tract, distension of the esophagus or stomach, and possibly severe damage and internal bleeding. Large doses may produce gastritis and esophagitis, rupture of the colon, proctitis, and ulcerative. Ingestions of industrial strength peroxides can result in severe burns of the oropharynx and gastrointestinal tract, may cause obstruction of the respiratory tract, and may result in mechanical asphyxia. In higher strengths, it could be immediately dangerous to health and life.


Why do Practitioners Use These Two Dangerous Therapies?

Proponents of oxygen therapy contend that ozone and hydrogen peroxide, with their extra atoms of oxygen, are more efficient than ordinary O2 for fighting disease and repairing injury. They argue that increased oxidation in the body can neutralize toxic substances and kill invading microorganisms; and they advocate oxygen therapy for everything from infections to chronic fatigue.

The reality is that these forms of therapy do not get oxygen into the cells as suggested in their misguided theories. In normal breathing, oxygen from the air enters the lungs where the hemoglobin portion of the blood captures it. The human body automatically adapts to the amount of oxygen it receives by changing breathing rate. Blood returning to the lungs contains the surplus oxygen, which we then exhale. In mountainous regions where the air pressure is lowest, humans readily adapt to reasonably reduced levels of oxygen in air. However, when taking oxygen into the stomach through a liquid, pill, or food, the body’s blood level of oxygen is not affected. The recommended dosage of “stabilized oxygen” products would provide less oxygen than taken in a single deep breath!

Distributors of oxygen tents and oxygen steam saunas claim that they will also enhance human life in some way. While it is possible for a device to add a tiny amount of oxygen to water in a sealed tank, soon after the water contacts room air, most of it will quickly bubble out. A human being would need gills to extract significant amounts of oxygen from water.

Neither ozone therapy (and the machines used to make and dispense the gas) nor hydrogen peroxide therapy (nor the solutions used for it) are approved by Health Canada.


Hyperbaric Oxygen Therapy (HBO2T) (Effective in Some Situations)

Hyper means increased; baric means pressure. During hyperbaric oxygen therapy, patients inhale pure (100%) oxygen (O2) under greater than normal atmospheric pressure. When breathing oxygen in a hyperbaric environment, the patient’s entire body, not just the hemoglobin, saturates with oxygen to many times the normal level. When breathed under pressure, oxygen hyper-oxygenates the blood plasma, the fluid portion of the blood, and diffuses into all fluids and tissues such as lymph, bone, muscle, tendon, cartilage, and nervous tissues. When a blood vessel is injured, some of these tissues may be cut-off from the main blood circulation, which severely limits the amount of oxygenated blood downstream and precipitates an accumulation of toxic cellular waste product in the damaged area. The cells that comprise these tissues can remain viable with the diffusion of oxygen from nearby capillaries, but the level of oxygen they receive is inadequate (hypoxia) for normal function or healing.

A critical tissue oxygen level of 30 to 40 millimetres of mercury (mmHg) is required to allow normal healing processes to occur and if this is not present, healing will be delayed. Factors that prevent or delay healing include the following: poor blood supply, scarring, swelling, inflammation, and infection. Hyperbaric oxygen treatment can positively influence all of these factors.

The red blood cell (RBC) is the normal transport of oxygen in the body. Located within the RBC, hemoglobin chemically binds to oxygen with an efficiency of 98%. The plasma normally transports very little oxygen; however, at elevated pressure, plasma can dissolve up to 15x more oxygen. This hyper-oxygenated plasma can reach areas of the body where blood circulation is restricted and oxygen levels are insufficient. HBO2T also increases the deformability of red blood cells, which facilitates their passage through compromised circulation in capillaries.

How is the increased pressure for this therapy achieved? A hyperbaric chamber is a specially designed unit that is able to contain increased pressure. There are two types of chambers: room for one person (monoplace) and room for more than one person (multiplace).

At sea level, the atmosphere is exerting approximately 760 mmHg or 14.7 pounds per square inch (psi) of pressure on our body. Normal atmospheric pressure is 1.0 atmosphere absolute (ATA). The air inside the sealed chamber is pressurized which results in greater atmospheric pressure. The method used follows Henry’s Law. The manifestation of this law is demonstrated when one breathes a gas, such as oxygen, at elevated atmospheric pressure, the oxygen will dissolve in all body fluids in proportion to the surrounding pressure and solubility of the fluids and tissues.

The increased pressure enables more dissolved oxygen into the body’s tissues and fluids resulting in increased oxygen levels in the body, at a much higher amount than is possible without the use of pressure. Most treatments are between 1.1 and 2.5 ATA. Some conditions respond better at greater pressures, to an upper limit of 3.0 ATA.

Treatment occurs in three phases: compression, when the pressure in the chamber gradually increases to the therapeutic level; treatment, the duration while the chamber occupant(s) inhale pure oxygen; and decompression, when pressure is slowly returned to normal. Patients are usually awake during the entire procedure. Patients who are uncomfortable in enclosed, cramped spaces may find the single-place chamber anxiety-provoking. In such cases, a physician might prescribe a mild sedative before treatment.

The length and frequency of treatments depend on the patient’s illness. For example, the standard recommendation for smoke inhalation (carbon monoxide poisoning) is five 90-minute treatments followed by a medical evaluation to determine the need for additional sessions. Treatments for soft tissue injuries or tissues damaged by radiation therapy may require 2 hours in the chamber once-a-day for several weeks. Some chronic conditions, such as Crohn’s disease and other non-healing wounds may require therapy sessions on a long-term basis.

When breathed at elevated pressures, oxygen behaves like a drug. The dose of the oxygen provided will depend on how much pressure is used, how long the pressure is maintained, and the frequency and total number of treatments.

It is important to note that, in most cases, HBO2T is not a stand-alone treatment. Among the few indications for which HBO2T is a primary treatment are scuba-diving accidents, gas gangrene, carbon monoxide poisoning, and severely hypoxic conditions. In the majority of conditions, HBO2T is most effective when combined with other therapies such as pharmaceuticals, physical therapy, nutritional counselling, acupuncture, massage therapy, and surgery. Often these therapies occur concurrently during an HBO2T session. This is the case with physical therapy, in which a therapist can stay with the patient in a multiplace hyperbaric chamber while administering treatment.

Hyperbaric oxygen also has an antibacterial effect. To bacteria that live without oxygen (anaerobic bacteria), exposure to oxygen is poisonous. In addition, since much of the body’s immune system is oxygen-dependent, high oxygen levels can give a boost to the white blood cells that fight off infection, particularly deep in the tissues. Hyperbaric oxygen can also compensate for disrupted circulation by helping to reduce swelling and promote angiogenesis tissue recovery following burn or crush injuries.

Other applications of HBO2T are still experimental (used off-label). Some plastic surgeons recommend hyperbaric treatment to ensure tissue grafting and to stimulate collagen production, to hasten healing after the operation. In some animal and clinical studies, hyperbaric oxygen has shown promise for treatment of stroke.

Hyperbaric oxygen chambers are expensive and are usually found in large hospitals and medical centres, near an emergency department. More recently, out-of hospital hyperbaric oxygen clinics are popping up all around. These centres use HBO2T to treat chronic medical conditions for which there is strong published evidence of its effectiveness. Use caution in determining if a centre conforms to safety standards and is capable of providing the depth of atmospheric pressure required for your particular need.


What Side Effects May Occur?

Before clearing a patient for treatment, a physician reviews the patient’s medical history form. Most of the contraindications to HBO2T involve current lung disease or injury, upper respiratory tract infection (sinus infection/ common cold), and complication from ear surgery.

The most common side-effects from receiving HBO2T occur while the chamber is being pressurized or depressurized. These are middle ear barotrauma, sinus pain, and pulmonary barotrauma. In fact, pain may occur in any body cavity where air can get in but can’t get out. For example, dental pain may occur if a filling has trapped air beneath it. In rare cases, pressurization may rupture an eardrum. Some expected sensations include popping in the ears similar to that experienced in a descending aircraft.

Certain medications and concurrent therapy may not react as intended with HBO2T. It is very important that all medications (prescription and over-the-counter) be reported to the healthcare practitioner overseeing the chamber session. Some patients receiving long-term treatment might develop myopia and cataracts. Pregnancy was once considered a contraindication for hyperbaric therapy but it is now deemed acceptable if a condition left untreated will cause long-term damage to the mother or fetus, for example, pregnant women with carbon monoxide poisoning, which is toxic to both mother and child, benefit from HBO2T.

Under rare circumstances, HBO2T treatments may predispose the patient to an oxygen seizure without any recognizable risk factors. To reduce the possibility of a seizure, air-breaks are included in any therapy session where the treatment is elevated above 2.0 ATA.



When trained professionals administer HBO2T, it is a reasonably safe, non-invasive, and effective treatment. There are increased health benefits associated with using HBO2T in treating many conditions, including Crohn’s disease, in combination with other therapies. Many conditions respond well to HBO2T although each case produces individual results.

HBO2T is not a cure-all; however, it has given hope to many individuals who have exhausted all other treatment alternatives. This therapy successfully treats a number of medical illnesses (many already approved by Health Canada and paid for by insurance). HBO2T shows promise as a treatment for fistulising Crohn’s disease. Local hypoxia due to chronic inflammation and vascular injury may be an important factor in the pathogenesis of the disease. Restoring oxygen delivery to the tissue may reverse this process.


Whom can I contact if I have further questions?

For questions specifically regarding HBO2T installation, you may call the Medical Officer of Health in your municipality. For questions regarding the credentials of a physician operating a facility, call the College of Physicians and Surgeons in your province. For questions dealing with device licensing, call the Medical Devices Bureau, at 613-957-4786. For reports of adverse events, please call the Medical Devices Hotline at 1-800-267-9675.

The following references will provide more information on hyperbaric oxygen chambers and therapy:

  • Health Canada www.hc-sc.gc.ca/hl-vs/iyh-vsv/med/hyper-eng.php
  • Jain, K.K. Textbook of Hyperbaric Medicine. Third ed. 1999.
  • PM Tibbles, JS Edelsberg, Hyperbaric oxygen therapy, New England Journal of Medicine, 1996, v334, n25, p1642.
  • PS Grim, LJ Gottlieb, A Boddie, E Batson, Hyperbaric oxygen therapy, JAMA, 1990. v263, n16, p2216.
  • CSA Z275.1-93 (Revised 1998) Hyperbaric Facilities, Canadian Standards Association.
  • ASME PVHO-1a-1997 Safety Standard for Pressure Vessels for Human Occupancy, American Society of Mechanical Engineers.
  • Guidelines for Monoplace and Multiplace Hyperbaric Chambers, Undersea Hyperbaric and Medical Society (UHMS) www.uhms.org

Gail Attara, President & Chief Executive Officer, GI Society
First published in the Inside Tract® newsletter issue 124 – March/April 2001
1. http://www.hc-sc.gc.ca/cps-spc/pubs/cons/ozone-eng.php
2. Workplace Hazardous Materials Information System http://hc-sc.gc.ca/ewh-semt/occup-travail/whmis-simdut/index-eng.php