The caduceus, also known as the Staff of Hermes, is the symbol for Hermes in Greek mythology. It features two snakes winding around an often winged-staff. The two snakes are often associated with trade, eloquence, negotiation, alchemy, wisdom, and controversially, thievery, lying, and the passage into the underworld. How this symbol became associated with health and medicine is unknown. However, the use of the caduceus was exacerbated when the U.S. military adopted it as a symbol of the medical department in the late 19th century.
See also: Hermes