Hyperbaric oxygen therapy involves breathing pure oxygen in a pressurized room or tube. In a hyperbaric oxygen therapy chamber, the air pressure is increased to three times higher than normal air pressure. Under these conditions, lungs can gather more oxygen than would be possible breathing pure oxygen at normal air pressure. 

Hyperbaric oxygen therapy is a well-established treatment for decompression sickness, a hazard of scuba diving. But it also can be used to treat serious infections, wounds that won't heal and carbon monoxide poisoning.