What is a caduceus?

The caduceus was the magic staff of Hermes (Mercury), the god of commerce, eloquence, invention, travel and theft, and so was a symbol of heralds and commerce, not medicine. The words caduity and caducous imply temporality, perishableness and senility, while the medical profession espouses renewal, vitality and health.

The caduceus traditionally features two snakes winding around a winged staff. It is often mistakenly used as a symbol of medicine instead of the Rod of Asclepius, especially in the United States. Unlike the caduceus, the rod of Asclepius has only one serpent and no wings. The link between the caduceus of Hermes (Mercury) and medicine seems to have arisen by the seventh century A.D., when Hermes had come to be linked with alchemy. Alchemists were referred to as the sons of Hermes, as Hermetists or Hermeticists and as "practitioners of the hermetic arts".