Why are snakes on the medical symbol?

There are actually two versions of the symbol. The winged version is known as a caduceus, andthe stick is actually a staff that was carried by the Olympian god Hermes. In Greek mythology, Hermes was a messenger between the gods and humans (which explains the wings) and a guide to the underworld (which explains the staff). Hermes was also the patron of travelers, which makes his connection to medicine appropriate because, in the olden days, doctors had to travel great distances by foot in order to visit their patients.

In one version of Hermes' myth, he is given the staff by Apollo, the god of healing. In another version, he receives the staff from Zeus, the king of the gods, and it is entwined with two white ribbons. The ribbons were later replaced by serpents, as one story tells that Hermes used the stick to separate two fighting snakes , who then coiled around his staff and remained there in balanced harmony.