Opinion: Why is there a snake on the pharmacy symbol?

The image of a snake coiled around a bowl has become one of the world's most recognisable symbols of pharmacy, appearing on pharmacy signs, logos and professional emblems across many parts of Europe and beyond. Yet few people know how an animal so often associated with danger became linked with medicine.

The answer lies more than 2,500 years ago in ancient Greece, where snakes were closely connected with religion, healing and the mysterious power of natural substances. The symbol still seen on pharmacy signs today, known as the Bowl of Hygieia, carries echoes of those ancient beliefs.

The image of a snake drinking from a vessel is far older than pharmacy itself. It appeared throughout the ancient Mediterranean from as early as the second millennium BCE in religious and funerary settings. In early Greece, painted snakes approach to drink from the rims of cups or jugs placed in tombs, symbolising offerings made to the dead and the continuing relationship between the living and the underworld.

By the fifth century BCE, the motif had taken on a more specific meaning. As I have argued in previous research, Spartan artists produced stone and clay reliefs showing seated heroes offering a drink to a snake from a wine cup. These heroes were exceptional local mythical or historical figures honoured after death. The snake represented the powers of the underworld, while the act of offering a drink reflected the hero's role as a mediator between the human and divine worlds. Nourishing the snake was a ritual act that reassured worshippers that powerful underworld forces remained favourable. As Greek culture spread, so did the drinking snake. Artists in southern Italy incorporated the image into familiar myths, including the story of Heracles and the Garden of the Hesperides.

In these scenes, the Hesperides are often shown feeding Ladon, the great serpent that guarded the golden apples of immortality. The scene is sometimes interpreted as an attempt to distract or drug the serpent so Heracles could steal the apples. I see it differently. The Hesperides appear feeding Ladon even when Heracles is absent, suggesting this was not a trick but a regular ritual. Like priestesses who cared for sacred snakes, they were nourishing the guardian entrusted with protecting a divine treasure.

A different version of the motif appears in the story of Medea and Jason. Medea offers a bowl to the dragon guarding the Golden Fleece, but this time the contents have been altered. She mixes drugs into its usual nourishment, sending the dragon to sleep so Jason can seize the fleece.

These two myths reveal opposite uses of the same motif. In one, the bowl sustains and strengthens the guardian. In the other, it becomes the means to overcome it.

This brings us to an important Greek word: phármakon. The word could mean both a remedy and a poison. Whether a substance healed or harmed depended on how it was prepared, combined and used.

That idea appears throughout Greek literature. In Homer's Odyssey, the sorceress Circe uses phármaka to transform Odysseus' companions into swine. Later, she uses another preparation to restore them to human form and even rejuvenate them. The same knowledge that could bring harm could also bring healing.

The dual nature of phármakon helps explain why the drinking snake eventually became associated with Hygieia, the daughter of Asclepius, the Greek god of medicine. Hygieia personified health, cleanliness and wellbeing, and the image of a snake drinking from her bowl gradually became the enduring symbol of pharmacy.

Some scholars have even suggested the snake is not drinking at all, but releasing venom into the bowl. This interpretation is particularly fitting because snake venom itself embodies the ancient idea of phármakon. In large quantities it can be deadly, yet in carefully controlled doses it has valuable medical applications. Like all medicines, its effects depend on knowledge, preparation and dosage.

Although the Bowl of Hygieia has long since lost much of its original mythological meaning, it continues to symbolise an enduring truth about medicine. The substances we rely on to heal can also cause harm if they are misunderstood or misused.

Whether displayed on a pharmacy sign, a professional emblem or a medicine-related logo, the snake and bowl represent an idea that has endured for thousands of years. Behind the familiar image lies an ancient reminder that the difference between poison and remedy often depends not on the substance itself, but on the knowledge and care with which it is used.

Dr Gina Salapata is an Associate Professor in Classical Studies in the College of Humanities and Social Sciences at Te Kunenga ki Pūrehuroa Massey University.