In case of injuries, the US army provides a First Aid Packet to each soldier. Each packet made of different materials throught the war, contains one bandage and one Sulfanilamide packet (A white powder to put on the wound). This type is made by Bauer & Black is painted in red. The origin of the red color was to indicate that the box was containing sulfanilamide as it is not stamped on the bottom (to stop using green paint and simplify the manufacturing process too).