Comment “oxygen” to learn more. Hyperbaric oxygen therapy (HBOT) is when a person goes into a chamber and receives high pressure oxygen. My husband healed colorectal cancer and this therapy was key to his healing. Here is how it works…Many areas of tissue damage or cancerous growth are characterized by a “low supply of oxygen” and HBOT can advance and speed up recovery in those areas. The increased oxygen enhances the ability of white blood cells to kill bacteria, reduces swelling and allows new