Stevenson, Dr. Henry Jekyll creates a potion that transforms him into an evil version of himself called Edward Hyde. Dr. Jekyll does not explain how he created this potion because he felt his “discoveries were incomplete,” he only indicates that it requires a “particular salt.” He uses the potion successfully to go back and forth between his normal self, Dr. Jekyll, and his evil self, Mr. Hyde. Popular ingredients used in potions Solanaceous plants In the 11th century, plants belonging to the nightshade family Solanaceae were often used as an ingredients in the potions - aphrodisiac or otherwise - and flying ointments of witches. The specific nightshades used in such concoctions were usually tropane alkaloid-containing species belonging to the Old World tribes Hyoscyameae and Mandragoreae. These potions were known as pharmaka diabolika ("devilish drugs"). The root of Mandragora officinarum, the celebrated mandrake, fabled in legend to shriek when uprooted, was often used to prepare sleeping potions, although it could prove poisonous in excess, due to its tropane alkaloid content. M. officinarum is native to the Mediterranean region. Administered in small doses mandrake root has been used in folk medicine as an analgesic, an aphrodisiac and a remedy for infertility. Larger doses act as an entheogen of the deliriant class, having the potential to cause profound confusion and dysphoria characterised by realistic hallucinations of an unpleasant character. Classical and Renaissance authors have left certain accounts of the use of the plant by witches in the preparation of potions intended variously to excite love, cause insanity or even kill. Scopolamine, a toxic, delirient alkaloid present in (and named for) Scopolia carniolica and also present in Mandragora, Hyoscyamus and other Solanaceae, was used by the infamous Dr. Crippen to kill his wife. Spanish fly In Ancient Greece, the spanish fly (also known as cantharides) was crushed with herbs and used in love potions. It was believed to be effective due to the bodily warmth that resulted from ingesting it. However, this was actually a result of inflammation from toxins in the tissues of the beetle. Ferdinand II of Aragon drank many potions and elixir contains the Spanish Fly. Cochineal Cochineal, another type of dye, replaced kermes as an ingredient in Confectio Alchermes in the 17th and 18th century. Cochineal was also heavily used as an ingredient in potions for jaundice. Jaundice potions were a mix of Cochineal, cream of tartar and Venetian soap