A caduceus (kerykeion in Greek) is a staff with two snakes wrapped around it.
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.
Its origins are thought to be as early as 2600 BC in Mesopotamia. It was used by the priests in the Eleusinian Mysteries of ancient Greece, and has been associated with the Gnostic Corpus Hermeticum and Kundalini Yoga, where it is thought to be a symbolic representation of the "subtle" nerve channels the "ida", "pingala", and "sushumna " described in yogic kundalini physiology.
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 (☤).