This article explores the links between chymical medicine, charity, and vocation in the writings and careers of Henri Rousseau de Montbazon and Nicolas Aignan, known as “the Louvre Capuchins” (les capucins du Louvre) because they operated a royally sponsored medical laboratory at the Louvre from 1678 to 1679. It shows that Rousseau and Aignan’s hybrid persona as chymical physicians and mendicant friars allowed them to leverage courtly values surrounding charitable poor relief into lucrative patronage under Louis XIV. Aignan in particular developed a detailed theological and natural philosophical defence of this identity, framing it as a recovery of the authentic vocation of the Christian priest-physician, a healer of bodies as well as souls. By the end of the seventeenth century, however, I argue that Rousseau and Aignan’s attempts to reconcile their identities as both friars and healers into a single persona were increasingly challenged by the medical establishment and their own order.