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By Sabrina Ruffino Giummara on

The symbols of medicine: a story of snakes, staffs and Greek gods

A common emblem for medicine depicts one or two snakes coiling up a staff. This symbol, often referred to as a ‘caduceus’, has been frequently used as a pharmacy or healthcare company crest. However, the term ‘caduceus’ has a distinct meaning and historically has been confused with the real first medical symbol: the ‘Rod of Asclepius’.
Copy of a pocket medicine chest with the rod of Asclepius on lid. The original was found in Pompeii.

The caduceus of Hermes

The term ‘caduceus’ comes from a Greek word meaning ‘herald’s wand’ and refers to the staff carried by the ancient Greek god Hermes – called Mercury by the ancient Romans. He was messenger of the gods, protector of travellers, shepherds and merchants, as well as the protector of thieves, liars and gamblers.

Terracotta figure of Hermes holding his caduceus, probably ancient Roman

Hermes’ caduceus is usually represented as two snakes winding up the length of a central staff, often surmounted by wings. According to the mythology, it was created when Hermes threw his staff at two snakes in the attempt to end a fight between them. The snakes stopped their battle and wrapped themselves around the rod. This combination of staff and two snakes became the symbol for resolving disputes peacefully. In time, it also became a mark of commerce. 

Bronze winged caduceus on marble base

Two snakes then, not one. This is where the confusion began – a staff with one snake is an attribute of another important Greek god: Asclepius.

The Rod of Asclepius

Several sources claim that Asclepius (Aesculapius for the ancient Romans) was first a physician hero, who was later recognised as the god of healing with a cult that spread in the 5th century BCE. Various sanctuaries in his name were built throughout Greece as areas of worship and refuges for the ill. These were hospital-like places where priests guided patients through rituals of purification and medical curative practices, regularly involving snakes as part of the healing process.

Asclepius is usually represented as an old, bearded man, leaning on a heavy staff with a single snake coiled around it, known as the ‘Rod of Asclepius’. The main difference between the caduceus and the staff of the god of medicine is the number of snakes. The staff of Asclepius, which figures one serpent, was soon associated with healing, becoming, throughout the ages, an established emblem of medicine and curative methods.

Marble statue of Asclepius, standing and leaning on a staff with a single snake coiled around it, probably ancient Greek

In his cult, Asclepius was often joined by his daughter Hygieia (also referred to as Hygeia or Hygiea), goddess of health, cleanliness and sanitation. The modern word ‘hygiene’ derives from the name of the goddess herself. Her symbol was the ‘Bowl of Hygeia’, which featured another snake. Since its first apparition on a coin by the Parisian Society of Pharmacy in 1796, the Bowl of Hygeia has been adopted by various pharmaceutical companies in the world and is a cup or chalice with a snake coiled around its stem.

Coin or medal by the Parisian Society of Pharmacy, depicting the Head of Hygieia and her bowl with snake on the left, 1796

Throughout human history and across the world, the snake has always had a mystic role, alternatively seen as a benevolent figure associated with the origin of the world and creation, or as a malevolent symbol of evil and death. The association between snakes and medicine is mainly due to the snake’s ability to shed its skin which led to snakes as a symbol of life, rebirth and renewal, and fertility.

In mythologies and legends, snakes have taken a significant role in the Eastern and Asian mythologies at least since 3000 BCE. In the Epic of Gilgamesh, a poem from ancient Mesopotamia (c.2000 BCE), a snake steals the secret of eternal life from the hero. Following this, the snake shed its skin and rejuvenated, and this is probably the first reference to the snakes’ ability to lose their skin and the conviction that snakes could live forever.

The origin of the Rod of Asclepius as a symbol is uncertain. In the Book of Numbers, dating to the 7th-6th century BCE, God tells Moses to cast a bronze serpent and place it on a wooden pole as a cure for a poisonous snakebite: anyone bit by a snake need only look at the staff to be healed of the snake’s venom. It is likely that stories from nearby cultures influenced the Greek world in the attribution of the snake-staff to the god of medicine.

An alternative origin theory can be found in an Egyptian document known as the Ebers Papyrus, one of the oldest medical works in the world. It refers to the method of removal of a parasite. Known as guinea worm and growing up to 80cm, the parasite usually migrates just beneath the skin, forming a blister. To remove it, physicians would cut open the blister on the patient’s skin and, as the pest wiggled out of the cut, they would carefully curl it around a stick until the entire animal had been removed. A worm wrapped around a stick as opposed to a snake coiled around a rod.

Pharmacy jar with Rod of Asclepius representation, French, c. 1770-1830

Caduceus and medicine

Although the caduceus (two snakes, not one) had a non-medical origin, during the late Middle Ages and the Renaissance it started to be associated with the healing professions, as an emblem of alchemy and then later, pharmacy. The source of this correlation appears to be the Hermetica manuscripts, a collection of texts on philosophy, astrology, alchemy, magic, and medicine.

The manuscripts were attributed to the mythical character of Hermes Trismegistus, the name that the ancient Greeks had applied to the ancient Egyptian god Thoth, scribe of the gods, the inventor of writing and the patron of all the arts dependent on writing, and that they had identified with their god Hermes.

The manuscripts were thought to contain divine revelations from the god Hermes-Thoth and became the foundation of medieval alchemy. Alchemists considered Hermes-Mercury a central figure: he was the divine magician, the patron of grammarians and philosophers, and revealer of secret knowledge. After him was named the fasted planet to orbit around the Earth, Mercury, and, some time later, the metal associated with it, quicksilver. One of the most important alchemical elements used by the alchemist, quicksilver (or mercury) is a silver liquid metal thought to be the fundamental component of all matter. It was one of the main ingredients for the philosopher’s stone, which allegedly turned normal metals into gold. Medieval alchemy used the caduceus, attribute of the god Hermes-Mercury, as a symbol to indicate preparations containing mercury.

The Hermetica texts were extremely influential during the Renaissance, and inspired major intellectuals as Marsilio Ficino, Giovanni Pico della Mirandola and Giordano Bruno. Alchemy and the alchemists’ experiments with chemicals, observations, and theories surrounding medical, pharmaceutical and occult subjects laid the foundations for the future professional fields of chemistry, mining, metallurgy, pharmacy and medicine. Because of the link between alchemy and pharmacy, and the use of mercury in pharmaceutical preparation, from the 16th century onwards the caduceus started to appear as a symbol linked to healing, and it can also be found occasionally as printers’ marks in frontispieces of pharmaceutical publications.

Gilt wood and plaster winged caduceus, probably an apothecary’s sign, French, c. 1840-1910

Modern Era

However, it wasn’t until the modern era that the symbol of the double-snake wrapped around a winged staff became mistakenly popular as a medical emblem, probably due to the loss of its original associations. In 1792, a surgeon dentist, Josiah Flagg Jr., used the caduceus in an advertisement in the Boston Columbian Sentinel. The double snake-staff reappeared on titles pages of books by Londoner medical publisher John Churchill in the 1844, although he probably did not intend it as a medical symbol, since he used the staff of Asclepius in some other of his books as well.

It is speculated that the official use of the caduceus in modern medicine was introduced by the United States Marine Service in 1857. In 1902, it formally came to represent the U.S. Army Medical Service and the U.S. Public Health Service, after the latter adopted it in 1881.

It was used on the collar of uniforms, and it is unclear whether the U.S. Army Medical Corp were aware of it being a non-medical emblem. It has been long discussed whether the caduceus was deployed as a symbol of neutrality, an extension of its original meaning to encompass medical personnel as non-combatants during conflicts, or if there was a mistake in the iconography, and it was meant to carry the medical significance of the Rod of Asclepius. Whatever the case might be, the caduceus’ use by a Government medical body led to its popularisation as emblem of medicine globally.

Over time, however, many medical and pharmaceutical organisations have modified their logos to remove the caduceus and return to the roots of the Rod of Asclepius. For example, the caduceus was briefly used as an emblem by the American Medical Association, but in 1912, after much discussion, the staff of Asclepius was adopted and is still in use. Many medical schools in the United States have also replaced the caduceus in their crest, including the Association of American Medical Colleges.

Although the caduceus is still accepted as medical emblem in some parts of the world, particularly in the United States (where its use is advocated especially in military medicine), most of the world now recognise once again the staff of Asclepius as the emblem to represent medicine and healing. Today, you’ll see the Rod of Asclepius as a symbol of many health organisations, including the World Health Organisation.

London Ambulance crest on a base layer jacket depicting the rod of Asclepius


Despite being thousands of years old, ancient Greek symbols still remain relevant today and can be found all around us. The snake-staff emblem is one of them, although it is worth keeping count of the number of reptiles involved.

The caduceus, attributed to the Greek messenger of gods, Hermes, has two snakes entwined around a staff surmounted by wings. In its primary form, the caduceus represents peace, neutrality and commerce, and with this meaning can be found on many coats of arms and flags around the world. You can see it in this 1/2d stamp commemorating the Festival of Britain. Issued in 1951, it figures Britannia’s head with a cornucopia, representing Prosperity, and the caduceus, representing, in fact, Commerce.

2 1/2d stamp commemorating the Festival of Britain, issued in Great Britain 3 May 1951 and designed by E Dulac

On the other hand, the Rod of Asclepius, associated with the Greek god of healing, Asclepius, figures only one snake and has no wings. Considering the original meaning of these symbols in Greek mythology, the staff of Asclepius holds a stronger connection with the medical field. Another popular pharmaceutical symbol is the bowl of Hygeia, his daughter’s attribute.

Cameo depicting Hygieia, with snake coiled around her left arm and a bowl held in the right hand

That said, the success of the caduceus as symbol is undeniable. All over the world, people are familiar with the two snakes that adorn the winged staff. Its peculiar name, ‘caduceus’, it is often wrongly assigned to the staff of Asclepius, which, on its part, hasn’t got a specific name. Next time you see a staff and some snakes, hopefully you’ll be able to diagnose it correctly as belonging to Hermes or Asclepius.