ᶜAbbās Wasīm Efendi was born in Bursa in 1689 and died in Istanbul in 1760. He was a physician, astronomer, calligrapher, and poet during the reign of Sultan Mustafa III (r. 1757-1774). He was a physician who made significant contributions to the improvement of medicine in the Ottoman state. He wrote and translated many works on medicine and pharmacology, and used the information at hand in his many contacts with European physicians who visited Istanbul. This paper focuses on ᶜAbbas Wasīm because through his work and the work of those physicians around him, Ottoman medicine, began to turn its face towards Western medicine, although it remained rooted firmly in the tradition of Islamic medicine. The main contribution of ᶜAbbās Wasīm to Ottoman medicine literature is his work Dustūr Wasīm fī al-Ṭibb al-jadīd wa al-qadīm (Turkish, 1748, 850 folios), an important book consisting of both modern European and traditional Turkish-Islamic medical practice which ᶜAbbas Wasīm attempted to combine. He used both European and Eastern Islamic medical sources, which he compared in a methodic way. In addition to other physicians’ studies, in some cases he added his own experiences. His book played an important role in the transmission of the new European medicine to the Ottoman world. In the prologue, he says that to become a good physician, one should learn physics and chemistry as well as medicine. He then mentions the major rules of medicine, which every physician should know. The first chapter concerns diseases of internal organs; the second chapter women’s and children’s illnesses; the third chapter tuberculosis and panniculus; the fourth chapter simple and compound drugs. At the end, he presents advices to the physician.