From antiquity, Galenic physicians extensively discussed the active powers of simple and compound drugs. In their views, simple drugs, that is, single ingredients, acted according to their material qualities and the properties of their substance. As for compound drugs, their efficacy resulted from the mutual interaction of their ingredients and their modes of preparation. In the late Renaissance, Galenic physicians and naturalists, such as Leonhart Fuchs and Pietro Andrea Mattioli, attempted to explain these pharmacological properties or “faculties” at the intersection (...) of medicine, botany, and natural philosophy. This chapter examines the case of the Italian physician and botanist Andrea Cesalpino. His pharmacological treatise De medicamentorum facultatibus [On the Faculties of Drugs, 1593] was particularly significant for its reception of ancient and medieval texts on drug properties, materia medica, and the role of the senses in the knowledge of bodies. (shrink)