A device for processing respiration gas with a filling of an oxygen-releasing chemical in a cartridge that can be received in a housing to which the respiration gas connection can be connected. The filling can be accommodated in a simple, inexpensive cartridge without having to give up protection from water vapor, as a result of which an inexpensive consumable part is to be obtained. To achieve this, the cartridge 1 is closed off with at least one bottom 8 that can be pushed into the inside of the cartridge and has openings 7 in it and is surrounded with a foil 10 that is impermeable to water vapor in a vacuum-tight manner (FIG. 1).