Studies indicate HBOT is an epigenetic therapy in the broad sense. The combination of hyperoxia and increased pressure act at the epigenetic level to differentially and temporarily alter gene expression and suppression of over 40% of all protein-coding genes. The net effects are permanent tropism and tissue repair and temporary and permanent inhibition of inflammation and apoptosis. By mechanisms involving oxygen-sensitive gated membrane ion channels and pressure-induced strain on cell and mitochondrial membranes,14,40 hyperbaric pressure and hyperoxia are two organically, and naturally, manipulating, ubiquitous natural-occurring agents that effect salutary changes in disease at the epigenetic level.