Poisoning is not a new phenomenon but it is a rare one indeed. Especially when it involves this many person in such a long period of time. Poisoning was a standard form of killing during the Middle Ages. It was considered a woman’s form of murder and because of this only cowards were known to practice the art. Yes, poisoning is an art that can be found in its diversity of application whether that be internal or external. There was also Poison Rings that were used by the waiters when bringing a guest their food. A nasty concoction of herbs and oils can be mixed and rubbed inside the material of a dress which will cause inflammation. Poisoning got so bad that if was categorized as a form of mania. I talk about this more in Kicked Out Of Heaven Vol. II

https://abcnews.go.com/International/man-suspected-killing-21-workers-poisoning-food-authorities/story?id=56230091