Folkloric information about magical spells pertaining to werewolves can be found at the LiveScience and University of Pittsburgh websites. Information at these sources covers folkloric spells for the creation and control or extermination of werewolves.
Despite their possible basis in the medical conditions of hypertrichosis (excessive hair growth), porphyria (hypersensitivity to light) and clinical lycanthropy (the delusion of being an animal), werewolves have long been associated with the occult, and magical explanations for their creation abound in folklore. An ancient Greek explanation held that a human would turn into a werewolf upon eating a mixture of human and wolf flesh. Humans were also believed to turn into werewolves simply by drinking water that a wolf had come into contact with, by eating a particular blend of herbs or by being cursed.
The full moon is also associated with the creation of werewolves, with conception under a full moon or even just sleeping under one on a Friday both once believed to be causative factors.
It was also believed in Russia and parts of Europe that humans could become werewolves through the use of a "wolf strap" gifted to them by the devil. Magical means of destroying werewolves in folklore included burning these straps, burning the werewolves themselves or shooting them with a silver bullet. According to legend, a silver bullet wound sustained by a werewolf would never heal and, assuming they survive being shot, would keep them in human form for the rest of their lives.