Hyperbaric oxygen therapy (HBO) is the administration of 100 percent oxygen at greater than normal atmospheric pressure. It is administered in a hyperbaric chamber. It is the primary treatment modality for acute carbon monoxide poisoning, acute gas embolism, and decompression sickness and is used as adjunctive treatment for compromised skin grafts, gas gangrene, acute cyanide poisoning, and Meleney's ulcer (chronic ulcer caused by microaerophilic streptococci). Evidence mounts to support the use of HBO as an adjunct in the treatment of osteomyelitis, osteoradionecrosis, and soft tissue injury. HBO is being investigated in research settings for a variety of other conditions; among them are burn injuries and acute cerebral edema(1,2). Hyperbaric facilities have become increasingly widespread, despite controversy over the use of HBO in nonresearch settings for an endless variety of conditions.