The caduceus was a symbol of commerce and is associated with the Greek god Hermes. It was originally a herald's staff, sometimes with wings, with two white ribbons attached. The ribbons eventually evolved into snakes in the figure-eight shape.
In modern times it is often used interchangeably with the Rod of Asclepius, associating the caduceus with medicine, especially in the United States. Historically, the two symbols had distinct and unrelated meanings.
In Unicode, the "caduceus" symbol is U+2624 (☤).