The delivery of oxygen to the wound site is crucial in healing diabetic foot ulcers, and impairment of this process in people with diabetes leads to delayed wound repair. Hyperbaric oxygen therapy works by elevating the plasma oxygen level. Fibroblasts synthesise and modify collagen, and both these activities require relatively high partial pressures of oxygen. Hyperbaric oxygen can promote healing by stimulating fibroblast activity and collagen formation. Increasing oxygen tensions also has a direct and toxic effect on anaerobes, therefore hyperbaric oxygen therapy has a special role in treating diabetic foot infections. Studies on hyperbaric oxygen therapy in general show it to be a beneficial adjunctive therapy for diabetic foot ulcers. However much of the work is anecdotal and more controlled trials are required.