 R. Gordon Wasson recounted the details of these deaths , noting the likelihood of Amanita poisoning . In the case of Clement VII , the illness that led to his death lasted five months , making the case inconsistent with amatoxin poisoning ( p . 110 ) . Natalia Naryshkina is said to have consumed a large quantity of pickled mushrooms prior to her death . It is unclear whether the mushrooms themselves were poisonous or if she succumbed to food poisoning . 
