The modern day symbol of medicine, otherwise known as the rod of asclepius is derived from the ancient greek symbol associated with the healing of the sick.Aesculapius was the god of healing in the ancient Greek pantheon and was instructed in medicine by the centaur Chiron. The rod of Asclepius symbolizes the healing arts by combining the serpent, which in shedding its skin is a symbol of rebirth and fertility, with the staff, a symbol of authority befitting the god of Medicine. Some scholars have suggested that the symbol represents a worm wrapped around a stick or rod. In ancient times, parasitic worms such as the guinea worm (Dracunculus medinesis) were common and were extracted from beneath the skin by winding the protruding end of the worm around a small stick. Early physicians may have advertised their skills, by posting a sign of a worm wound around a stick outside their practice.
Jones, James. 2007. Osteopathic medical history and philosophy. Retrieved March 17, 2009 from http://www.westernu.edu/bin/comp/11-07%20pdf/Hx%20of%20Osteopathy%20handout.pdf