This article examines the career and reform agenda of Christopher Merrett as a means of evaluating the changing conditions of medical knowledge production in late seventeenth-century London. This period was characterised by increasing competition between medical practitioners, resulting from the growing consumer demand for medical commodities and services, the reduced ability of elite physicians to control medical practice, and the appearance of alternative methods of producing medical knowledge – particularly experimental methods. This competition resulted in heated exchanges between physicians, apothecaries, and virtuosi, in which Merrett played an active part. As a prominent member of both the Royal Society and the Royal College of Physicians, Merrett sought to mediate between the two institutions by introducing professional reforms designed to alleviate competition and improve medical knowledge.These reforms entailed sweeping changes to medical regulation and education that integrated the traditional reliance on Galenic principles with knowledge derived from experiment and artisanal practices. The emphasis Merrett placed on the trades suggests the important role artisanal knowledge played in his efforts to reorganise medicine and improve knowledge of bodily processes.