Résumé : Within the field of the history of science, this dissertation examines late Renaissance physiology as junction of medicine and theories of matter. The term “physiology” refers to the theoretical part of Renaissance medicine that dealt with the structure and functioning of the healthy human body, while the term “theories of matter” designates the doctrines concerning the ultimate principles of physical nature, the human body included. By means of a comparative analysis of Latin medical treatises published between 1567 and 1634, this dissertation explores the physiological theories of a series of physicians, and in particular their interpretations of the composition of the living body. In so doing, it also evaluates their respective reception of Galenic medical philosophy and the way the latter was adapted to Paracelsian, atomistic and corpuscular conceptions that flourished in the late Renaissance. It is shown that the physiological theories of the protagonists of this dissertation ended up promoting a definition of elements as minimal discontinuous particles, which in the early seventeenth century became amalgamated with the notion of atom.