Hyperbaric Oxygen Therapy (HBOT) involves respiration of oxygen at high atmospheric pressures, typically 2.4 to 2.5 atmospheres.  Although firm scientific evidence for the efficacy of HBOT is several diseases is hard to achieve, physiological knowledge of respiratory and metabolic gas exchange help to explain the potential benefits. This presentation will give an overview of the physiological actions and the rationale for using HBOT therapy as an adjunct to “Classical” wound healing.  HBOT is currently used as adjunct therapy with patients undergoing treatment of cancer to reduce inflammation in bones and adjacent tissues where radiotherapy may cause damage - it seems to have an ability to reduce secondary radiation damage after radiotherapy. For example a study (HYPON) showed that the use of HBOT could reduce jaw bone damage in patients given radiotherapy for head and neck cancers. Radiotherapy damages surrounding tissues, not just cancer cells. Other uses include the regeneration of blood vessels - blood supplies may be restricted to tissues and bones by the harmful action of radiotherapy; and oxygen treatment can help significantly. Many of the effects of HBOT are still to be explained by science; however, there is an increasing body of knowledge through RCTs that are able to demonstrate it’s potential.