Therapeutic effect of hyperbaric oxygen in psoriasis vulgaris .Psoriasis is a chronic, remitting and relapsing, immune-mediated inflammatory skin disorder with a strong genetic predisposition. It is among the most common immune-mediated diseases in humans. the anti-inflammatory and immunosuppressive properties of HBO2 might account for its efficacy .Most of the psoriatic lesions were cleared, with marked reduction in itching and scaling. No side effect was reported with the use of HBO2. The patient also reported less pain in his hands and joints after the eight sessions of HBO2.