The affair of the poisons
When unexplained deaths multiplied at the French court in the 1670s, Louis XIV set up a special court to investigate poisonings. Between 1679 and 1683 more than 400 people were tried and 87 were sentenced to death as sorcerers and poisoners. The notorious Catherine Voisin, who sold love potions and poisons, laced drinks with henbane, thorn apple, Spanish fly and arsenic.
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.
Flour sprinkled on wounds: yarrow