The seventeenth century witnessed an intense debate about medical ideas.In Paris, in particular, there weredifferent conceptions about the best way to cure diseases, and many books describing procedures for preparing medicines were edited. Many of these publications were compilations of old recipes adapted to the era, often bringing up-to-date products that became available in Europe after the discovery of the "New World". Such booksinclude La Chymie Charitableet Facile en Faveur des Dames, originally published in 1666, and apparently the only work signed by Marie Meurdrac. Marie Meurdrac’s recipes were based on her understanding about the matter, which, according to her, was formed by a universal and unique principle that generatedthree others, namely: mercury, sulfur and salt. These, in turn,formedthree other principles,bearing different qualities present in the final products of distillation, as demonstrated by experiments.Meurdrac’striadicconceptions were also based on the Holy Trinity. Consequently, they diverged from the tenets maintained by the teachers of the King’s Garden, who tended to accepttwo additional principles obtained by distillation or through reduction by fire. Considered passive, thesetwo principles were water and earth. It is possible the Meurdrac’sternary principles were influenced by JosephDuChesne,who states in his Traicté de la Matiere(1626) that matter was formed by three principles that existed in the same essence,but distinguished themselves by their properties,similarly to the mystery of the Holy Trinity. For both Meurdrac and Du Chesne, the purest “spirit” could be obtained bysuccessive distillations.Even though presentin La Chymie Charitable, the ideaof preparing medicines by the distillation of curative substances, separating pure essences from impure matter, derives from fifteenth-century books of distillation.Distillation ensured the excellence of the final products because this method furnished the subtlest part of any material.Thus, the aim of this paper is to present some considerations about the operations and techniques used by both authors to obtain medicines.