Two snakes or one? How we get the symbol for Medicine wrong

Healthcare is full of antiquity, not surprising for a venture as old as humanity itself. Humans have always got sick and always turned to wise men and women and the divine to help them. With that comes symbols and provenance. Wound Man. The Red Cross. The Rod of Asclepius.

Ah yes, the Rod of Asclepius, the Ancient Greek God of healing. It’s a prominent symbol of Medicine. One staff, with two snakes entwined around it…

Except that symbol is not the Rod of Asclepius at all. That symbol of two snakes wrapped around a pole, known as a caduceus, actually belonged to Hermes, the Ancient Greek messenger God in charge of shepherds, travel and commerce. The Ancient Romans called him Mercury. The fastest of the gods, he had winged shoes and helmet to help him travel. On one adventure he saw two snakes fighting. To stop them he threw a stick at them and at once the serpents wrapped themselves around it and became fixed. Hermes liked the resulting staff so much he took it as his own. Hence the caduceus became a symbol of Hermes; of commerce and travel.

Asclepius (Vejovis to the Romans) on the other hand was the son of Apollo the Sun God. Just like Hermes Asclepius was also linked to snakes. One story has a snake licking his ears clean and in so doing giving him healing knowledge. Another story has a snake giving him a herb with resurrecting powers. For whatever reason, Asclepius would show his gratitude to snakes by carrying a staff with one snake on it. Not two. One.

The Ancient Greeks weren’t the first or last civilisation to link snakes to divinity. People have a habit of venerating and fearing in equal measure. Snakes, with their stillness, mysterious venom and supposed powers of self-renewal through shedding their skin are always going to inspire wonder.

So why the confusion between these two symbols? One possible reason is due to alchemy; the attempt by early scientists to turn base metals to gold which, while a folly, helped advance scientific knowledge including Medicine. The caduceus was used as a symbol by alchemists as they often used mercury or quicksilver in their preparations. Hermes/Mercury was linked to the metal that bore his name and so a connection was made. However, the caduceus was also a symbol of professionalism and craft. Therefore anyone wanting their work to be taken seriously would include the caduceus as a kind of early precursor of professional accreditation. In that vein when John Caius, the chronicler of sweating sickness, presented both the Cambridge college which bears his name and the Royal College is Physicians with a silver caduceus it was not as a symbol of Medicine but of professionalism.

In any case, in Great Britain, as late as 1854, the distinction between the rod of Asclepius and the caduceus as symbols of two very different professions was apparently still quite clear. In his article On Tradesmen’s Signs of London A.H. Burkitt notes that among the very old symbols still used in London at that time, which were based on associations between pagan gods and professions, “we find Mercury, or his caduceus, appropriate in trade, as indicating expedition. Esculapius, his Serpent and staff, or his cock, for professors of the healing art”

It seems the mix up didn’t take place until the 20th century. In 1902 the US Army Medical Corp adopted the caduceus as their symbol. The reason isn’t clear as the American Medical Association, Royal Army Medical Corp and the French Military Service all would happily adopt the staff of Asclepius. This decision to choose the caduceus has been credited either to a Captain Frederick P. Reynolds or a Colonel Hoff. The American Public Health Service and US Marine Hospital would also take Hermes’s symbol as their own.

This confusion seems to be uniquely American and driven by commercialisation. In 1990, a survey in the US found that 62% of the professional associations used the Rod of Aesculapius while 37% used the Caduceus and 76% of commercial organizations used the Caduceus. Perhaps that makes sense as Hermes was the god of trade (or maybe that’s me being cynical). The World Health Organisation would choose the Rod of Asclepius for their emblem where it can still be seen today.

Medicine is full of symbolism. Symbols, like language, change their meaning. There was a time that healthcare was full of quacks and charlatans. The Caduceus was a mark of professionalism long before their were accreditations to be had. Using the two snakes is a nod to those efforts to make the trade professional and accountable. But if you want to be accurate, it’s the staff with one snake you’re after.

Thanks for reading.

  • Jamie

Originally published at on August 28, 2019. Doctor and Educator. Podcast Blog on Medical Education and History of Medicine

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