Abstract: A medical apparatus (10) for use in the treatment of an animal. The apparatus (10) includes a chamber (12) for accommodating at least one animal. The chamber (12) includes a first opening (26) for entry of each animal into the chamber (12). The first opening includes a door (30) for sealing the opening (26), such that the inside of the chamber (12) can be subjected to an increased atmospheric pressure relative to the pressure outside the chamber (12). The apparatus (10) also includes a means for increasing the atmospheric pressure within the chamber (12), and a means for supplying oxygen to each animal in the chamber (12) at a greater concentration that that found in air. At least one stall (36) is provided for retaining an animal in a desired position within the chamber (12). A fire deluge system for activation in the event of a fire inside the chamber (12) is also provided.