Are we sure about this?

https://pubmed.ncbi.nlm.nih.gov/11003127/#:~:text=The%20snake%20figure%20was%20associated,antivenom%20against%20their%20own%20poison.

We investigated the meaning and the roots of the snake's usage as a symbol of medicine, the medical profession, toxicology and toxinology by examining mythological, archeological data and a variety of texts from the ancient Greek world. The snake figure was associated with Asclepios, the ancient Greek God of medicine, and possessed benevolent properties. It was believed to be able to cure a patient or a wounded person just by touch. The snake is also connected with pharmacology and antisepsis, as snakes possess an antivenom against their own poison. The snake is related to sciences associated with poison and death, such as toxicology and toxinology, and it also implies a metaphysical idea. It is connected with the underworld, not only because it crawls on the ground, but because it can bring death, connecting the upper with the underground world. The ability of the snake to shed its skin has been associated with the circle of life, and the renaissance spirit also, ever since early Hellenic antiquity. Consequently, as a symbol of the modern medical profession, toxicology and toxinology, the snake twisted around a stick or the snake beside a pharmapeutic cup, which also implies the use of medicines or even poison, has its roots in the ancient Mediterranean area as proven by the archeological data combined with literary references. Its benevolent as well as its poisonous properties could be paralleled by the similar properties of medicines.