The history of diving started with a simple breath-hold submergence in water; salvage and tunnel industries pushed the next wave followed by recreational and adventurous interests. Finally the modern hyperbaric oxygen (HBO2) therapy evolved. Military applications played an important role in developing key apparatuses, submarines, and other underwater vehicles. Meanwhile, the medical profession was never too far away providing undersea medical services as well as treating and preventing acute decompression illnesses. Nowadays, most hyperbaric chambers around the globe are used for HBO2 therapy, which fi nally shake the image of “a therapy in search of diseases” to become the evidence-based therapy. Wound care dominates the need for HBO2 therapy for good reasons. In particular, HBO2 therapy is an indispensable therapeutic modality for microcirculatory compromised cases.