Definition: Hyperbaric Oxygen Therapy
By Mayo Clinic staff

Hyperbaric oxygen therapy involves breathing pure oxygen in a pressurized room. Hyperbaric oxygen therapy is a well-established treatment for decompression sickness, a hazard of scuba diving. Other conditions treated with hyperbaric oxygen therapy include serious infections, bubbles of air in your blood vessels, and wounds that won't heal as a result of diabetes or radiation injury. In a hyperbaric oxygen therapy room, the air pressure is raised up to three times higher than normal air pressure. Under these conditions, your lungs can gather up to three times more oxygen than would be possible breathing pure oxygen at normal air pressure.  
Your blood carries this oxygen throughout your body, stimulating the release of substances called growth factors and stem cells, which promote healing.