Henbane in the beer
In medieval Europe henbane seed was added to beer to make it more intoxicating. In German henbane is Bilsenkraut, and the name of the Bohemian town of Pilsen is thought to come from it. The practice became so common that in 1507 Eichstätt banned brewers from adding henbane, and in 1649 Bavaria made it a severely punished offence. Henbane seed is poisonous.
Source: Jürgen Leo Müller, “Love potions and the ointment of witches: historical aspects of the nightshade alkaloids”, Journal of Toxicology: Clinical Toxicology 36(6), 1998 (Müller, Clin Toxicol, 1998). This is a folk record, not a treatment recommendation.
Worms falling from the tooth