theriake

Greek thēriakē meant a remedy against the bite of venomous animals — from thērion (wild animal, beast). The theriac (theriake) was one of the most famous medical preparations of the ancient world: a compound antidote believed to protect against all poisons. The Roman emperor Mithridates VI (132-63 BCE) was legendarily obsessed with the preparation, supposedly consuming poison antidotes daily to build immunity. The theriac bearing his name — Mithridatium — was one of the ancient world's most sought medical preparations.

Galen, the 2nd-century CE physician to the Emperor Marcus Aurelius, formulated his version of the theriac, which became the standard preparation for over 1,400 years. Galenic theriac contained 64 ingredients including opium, viper flesh, cinnamon, myrrh, saffron, and dozens of other substances. It was prepared in Venice and sold throughout the medieval world as a universal antidote.

The word treacle entered English through Old French triacle in the 14th century, still meaning the medical antidote. The shift to a sweetener began when apothecaries used the sticky, dark sugar syrup as a base for the theriac compound — the sweetness helped patients take the medicine. By the 17th century, treacle could mean either the antidote or the syrup used to make it palatable. The medicine dropped away; the sweet stayed.

Today treacle is British English for dark molasses or golden syrup — the sugary, thick, dark syrups used in cooking and baking. Treacle tart, treacle pudding, black treacle: the medieval antidote to viper poison is now a dessert ingredient. The viper flesh is long gone.