Sebastian Petrycy from Pilzno was one of the most eminent doctors in the Renaissance Poland, an outstanding intellectual active in several areas of knowledge. A graduate of the Krakow Academy. In 1589 he went to Padua to study medicine, which he probably started in Poland, because he had completed the Padua studies with a doctorate already in 1590. In terms of science, the medicine of Padua was very innovative. After returning to Poland, he was employed at the Krakow Academy, he lectured at the Faculty of Artium. In 1608 he became a professor at the Faculty of Medicine at the Krakow Academy and began teaching. He was a very popular and respected doctor, cared for both elite and poor patients. Petrycy left behind a rich literary output, incl. “Instructia or learning guide on how to exercise the time of moor” (Krakow 1613). However, the publication of the Krakow medic is clearly not a “pure”, classic instruction, it clearly has an “admixture” of the guide’s features. That is why considering the genological problems of this text is the subject of the philologist’s analysys. The specific genre syncretism of Petrycy’s “Instruction…” was demonstrated, the work was examined in terms of literary communication, the dependence assumed by the author between the recipient and sender, and therefore the dialogical nature of the text, the transmission of instructions, advice and tips was analyzed. It was established that the “Instruction…” is not characterized by “purity” of genre, that it evidently has a mixture of the features of science and a guide.