Mankind has always had a morbid fascination with poisonous plants. Over the centuries, poisonous plants have been used to remove garden pests—as well as unwanted rivals and deceitful partners. They have also been used for their medicinal qualities, as rather dangerous cosmetics, and even to help seduce a lover when perceived as an aphrodisiac. Some of these and other uses originate in a medieval book that has not yet been translated into English.