The caduceus is a symbol comprised of two snakes twining around a rod surmounted with wings. Its history can be traced back to ancient Greece. The Greeks recognized the caduceus as the symbol of Hermes (in Roman mythology it was the god Mercury). The caduceus became recognized in modern times as a symbol of commerce.
However, in the United States, the caduceus has often become confused with the Rod of Asclepius to represent medical organizations. Some historians trace the confusion back to the United States Medical Corps, which adopted the caduceus as its insignia in 1902. The Rod of Asclepius is used as a medical insignia in most medical organizations worldwide. But in the United States, according to one study, as many as 76% of the commercial healthcare associations use the caduceus, while 62% of professional healthcare associations use the Rod of Asclepius.