Treacle
A medicinal compound once in wide use as an antidote to poisons.
Treacle was a kind of salve.
It was reputed to be a remedy against venomous bites in particular and against poisons in general.
It also came to be considered a 'cure' for cancer.
The word 'treacle' descends from the Greek 'theriakos' (of a wild animal) and 'therion' (a wild animal).
Because wild animals may bite, these words gave rise to 'theriake' meaning 'antidote against a poisonous bite.' The Romans borrowed 'theriake' as 'theriaca' and the word eventually entered Middle French and, in time, Middle English as 'triacle.' Treacle today also refers to molasses or a blend thereof with sugar.
By extension, treacle is figuratively something very sweet, too sentimental, cloying.