The symbol with the single snake is called the Rod of Asclepius. It is the more widely used around the world, and it has the more credible association with medicine. In North America, the two-snake symbol called Caduceus may be more common but it also has a more tenuous connection with medicine.
The medical symbol you may be most familiar with, in North America at least, is one with two snakes that are intertwined around a winged rod. You may also have seen symbols that have a single snake around a rod or staff. It’s a little difficult to recognize any medical significance in this symbol.
The two-snake symbol
It turns out that the common medical symbol with two snakes is called the Caduceus. This staff was the symbol of Hermes in Greek mythology, and later associated the Roman messenger god, Mercury.
The Caduceus is a symbol of Hermes or Mercury in Greek and Roman mythology. Caduceus symbol is identified with thieves, merchants, and messengers, and Mercury is said to be a patron of thieves and outlaws…
This doesn’t sound very medical.
The other symbol – Rod of Asclepius
The symbol that has a single snake wrapped around a staff does have a direct association with medicine. It is called the Rod of Asclepius.
The Rod of Asclepius (or Staff of Asclepius) is an ancient Greek symbol that has become an internationally recognized symbol of medicine. It depicts a serpent entwined around a staff that is traditionally a knotty tree limb. The symbol is associated with the Greek demigod, Asclepius who was renowned for his unsurpassed medical prowess and healing powers.
In fact, much of the world recognizes this as the official symbol of medicine. The United States and Canada though tend to favour the Caduceus symbol.
Why doesn’t everyone use the Rod of Asclepius?
In the early 20th century medical organizations around the world were adopting the Rod of Asclepius as their symbol. These included the Royal Army Medical Corp, French Military Service. However, in 1902, the U.S. Army Medical Corp. adopted the Caduceus symbol, and that seems to have set the precedent for future adoption in North America.
There is some debate over whether there is a practical reason for the adoption of Caduceus over the Rod of Asclepius, and some justifications cited to combat the notion that it was adopted due to a mistake. These tend to center around the idea of Hermes as a peacemaker, or an association between Hermes and alchemy. These connections seem tenuous at best.
According to the New World Encyclopedia, a study was conducted in the United States in 2002 which found that “62 percent of professional associations used the rod of Asclepius, whereas in commercial organizations, 76 percent used the caduceus.”