The Leipzig physician Caspar Kegler created novel alchemical plague cures in the early sixteenth century that were among the first brand- name medicines developed in German- speaking lands. Although Kegler is largely unknown today, he and his descendants secured his fame by promoting his secret cures and distributing his printed pamphlets throughout German- speaking lands between 1521 and 1607. This article argues that Kegler’s work in creating and promoting novel cures represents a new sort of entrepreneurial activity among sixteenth- century physicians. Kegler’s case raises questions about the role of vernacular print and commercial motives in transforming early modern medicine to a more empirical discipline and explores how alchemy, persistent epidemics, and the turbulence of the early Reformation encouraged medical and cultural change. Since Kegler predates Paracelsus, his case also illuminates the depth of alchemical activities among German physicians in the early sixteenth century.