The Undersea and Hyperbaric Medical Society includes "select problem wounds" as an accepted indication for the use of hyperbaric oxygen (HBO 2 ), however, the treatment of diabetic foot ulcers (DFUs) has dominated any discussions of problem wounds because of the prevalence of DFUs in today's patient population and the reimbursement available for their treatment. Other wound types (eg, calciphylaxis ulcers, sickle cell ulcers, and pyoderma gangrenosum) that have well-deserved reputations as problem wounds have been infrequently treated with HBO 2 . While there are sound fundamental reasons why additional oxygen may have benefits in the treatment of these wounds, the challenge is finding enough high quality evidence to support routine use of HBO 2 .