Hyperbaric oxygen has been utilized in the treatment of radiation tissue injury for several decades. Most of the supportive basic science and clinical evidence stems from the management of mandibular osteoradionecrosis. More recently, the use of hyperbaric oxygen has been extended to other anatomic sites. This expanded use is based, in large part, on a presumed common underlying pathophysiology of LENT, regardless of its anatomic location. Supportive clinical evidence for these other sites is limited, however, and in need of a greater degree of scientific scrutiny.