In the recent studies of inter-cultural knowledge exchanges, translation holds an essential place. However, translation has been conceptualized only as an instrument for practical or useful knowledge, which eventually gave way to cultural appropriation and diffusion of knowledge. The head physician Hayatizade’s (d. 1692) medical treatises based on contemporaneous European sources offer an excellent vantage-point to challenge this argument. Copied multiple times during his lifetime, Hayatizade’s "el-Ris?’ilül-Mü?fiye li’l-emr?z?’l-mü?kile" embodies the first systematic medicinal translations into Ottoman Turkish from European languages. This endeavor of translation remarks not only a turning point in Ottoman medicine, but also reveals how translation was a mode of thinking as the craft of an early modern scholar during the process of knowledge production. By exploring how Hayatizade translated European medicinal texts into Ottoman Turkish, and what was lost and gained within the process, this paper demonstrates that translation was an epistemological instrument for early modern scholars, rather than only being a tool for knowledge transfer. Hayatizade’s decisions during the process of translation and organization of his works also provide insights for what made a medical translation successful in the early modern era. Rather than a commercially driven agenda to promote new materia medica from the Americas, I argue that Hayatizade’s treatise was mainly preoccupied with the state of medicine in the Ottoman lands, which sought a new ontological definition of disease.