Intermittent high dosage oxygen is a well-established therapy in many countries. Experimental and clinical studies have validated the use of hyperbaric oxygen in the reduction of oedema in the compartment syndrome (Sykhar et at, 1986), ischaemia (Nylander et al, 1985), crush injuries (Mathieu et al, 1990), plastic surgery (Davis and Hunt, 1989) and burns (Cianci et al, 1988). In the UK the method is little used, possibly because there is an unfounded fear of oxygen toxicity. Plasma oxygen transport is directly proportional to the partial pressure of the inspired oxygen and can be increased to such a level that haemoglobin transport is rendered unnecessary (Boerema et al, 1959), and tissue oxygen studies have shown that oxygen levels remain elevated for some hours after therapy. Football is frequently associated with minor injuries, involving joints, muscle, ligaments and tendons. A variety of therapies have been developed to reduce tissue swelling and preserve mobility. There is inevitably a compromise between early mobilisation with the risk of worsening the injury, and delaying the return to training, with loss of general fitness and, sometimes, disuse atrophy of muscle groups. Hyperbaric oxygen therapy has been used to determine whether the expected duration of injuries can be reduced. The patients studied were all professional footballers, injured either during matches or during training. The injuries were assessed by the club physiotherapist and an estimate made of the expected time before the players could be expected to resume full training. Treatment was then instituted with the usual physiotherapy techniques, but, in addition, sessions of hyperbaric oxygen were added on a daily basis until the players were fit to resume full training. The chamber (Hyox HTU) was pressurised on air and oxygen supplied via a Scott demand-valve system with overboard dumping of exhaust gas at 2 ata.