The caduceus derives from the Greek 'karykeion', meaning "staff of the herald". It was the symbol of the power to harm or to heal. It appears in images of the ancient Egyptian god of wisdom, Thoth, as a magic rod with twin snakes. Other variations show a staff entwined with twin serpents, topped with a pair of wings, or a winged sun and no snakes. Originally, those twin snakes may have been ribbons attached to the wings, eventually evolving into serpents.
Greek legend tells of a seer who, coming upon a pair of copulating serpents, tried to separate them by thrusting his staff between them. For his efforts he was transformed into a woman. Two snakes and a staff -- or wand -- became a symbol of transformative power.
In yoga, the caduceus represents the serpent energy of the Kundalini, the dual serpents suggesting both positive and negative energy. The staff is the spine, the serpent the energy, and the wings signifying the mind. Kundalini energy moves through the 'chakras' along the spine until it reaches the head, the temple of the mind. Many disciplines, schools of mystery, esotericism and magic have adopted the Hermetic caduceus because of its association with the intellect, mind communication, and its magical powers.
Today there are many more variations on the theme of the Caduceus, sometimes with the staff being replaced by a sword, a cross or a rocket, but always with one or two serpents in the picture. Video games, comic books, science fiction and animation have been inspired by the symbolism of this ancient emblem.
The Caduceus has long been a popular tattoo design with individuals who work in the medical profession.