Treatment of casualties enclosed in garments which protect them from a contaminated environment comprises attaching treatment apparatus containing uncontaminated treatment space to the protective garment and then effecting communication between the treatment space and the interior of the garment. The treatment apparatus comprises a generally rectangular enclosure having an access opening in one side with fastener means provided for closing the access opening. The fastener means are compatible with at least a portion of the fastener means for the protective garment to permit coupling the enclosure to the garment and then communicating the treatment space with the interior of the garment. The treatment apparatus includes an observation window opposite to the fastener device and sealed gloved openings to permit manipulation by treating personnel within the intercoupled treatment space and the interior of the garment. Provision is made in the treatment apparatus for the storage of various instruments, equipment and medication for use in treating casualties in the field.