A hyperbaric oxygen device 10 and methods of applying hyperbaric oxygen aredisclosed. Thedevice 10 comprises an enclosure 12 including a collapsible bag defined by twosheets 24, 26of fluid impervious material sealed together at both ends such that gas can bedeliveredbetween the sheets to inflate the enclosure to a rigid state and maintain theenclosure in therigid state when oxygen pressure in the interior of the enclosure is cycledbetween ambientpressure and above ambient pressure.