The poison taking, atleast its controlled, and they have antidotes for all the poison. All it does is make it so he's not susceptible to poison later. She really shouldnt have stopped that, and it's not like they cant handle it. Seems like they've been doing it for generations, they even said he was the strongest and most evil, so it's not gonna leave any long term effects and she knew he lived. She's gonna end up killing him first with how she does it.