Silver bullet: Or magic bullet. 1. The perfect drug to cure a disease with no danger of side effects. The term magic bullet was first used in this sense by the German scientist Paul Ehrlich to describe antibody and, later, the drug salvarsan that he created to treat syphilis. 2. In general, a magical solution to any vexing problem. 3. In werewolf lore, the only means to kill a werewolf (wolfman). See also: The Silver Bullet in Medicine.