Hyperbaric oxygen therapy (HBT) consists of inhaling 100% oxygen under pressure exceeding atmospheric pressure. Patients with various degrees of peripheral vascular disease (stages II, III, and IV according to Fontaine's classification) were treated with HBT. Clinical symptoms improved in 70%. Ankle/brachial index increased by more than 0.10 in 47%. Photoplethysmographic pulse appearance has been detected in roughly one third of patients. Transcutaneous oxygen tension did not, however, improve significantly. Plasma malondialdehyde (MDA) was evaluated as a marker of lipid peroxidation, possibly influenced by hyperbaric oxygen. Surprisingly, the authors found that MDA levels decreased after HBT, probably as a result of the activation of antioxidant systems. These results show that HBT represents a useful approach in the treatment of peripheral vascular disease, since it improves clinical and hemodynamic parameters, with no potentially harmful side effects, such as enhanced lipid peroxidation, at least in the short term.