Yu, Itae was a noted doctor who was active in the period of King Hyojong and King Sukjong. He wrote the medical books such as 〈Silheomdanbang〉,〈Inseogyeonmunrok〉, 〈Marjinpyeon〉, etc. and once participated in Royal medical council for curing the disease of King Sukjong. He is also famous for Yu itae tale which is wide spread in the area of Youngnam. This research is aimed at, on the basis of the precedent research, arranging his medical activities by tracing his deeds through the contents of historical records and his writings, based on which, clarifying several facts about compilatory process of 〈Silheomdanbang〉. Yu, Itae was versed in medicine and a paragon of filial piety. He left some records about measles when he was 41, and at that time his principle of medicine about measles was already established. On the basis of such an experience and academic idea, he finally came to write 〈Marjinpyeon〉. His broad knowledge of diseases beside measles was arranged in " Silheomdanbang"[ Inseo Travelogue] in 1709. Through this book, we can be aware that Yu Itae ranged over the experience-based medical procedures from other regions and also had an interest in even medical knowledge coming from abroad even though he inhabited Sancheong. His medical reputation spread not only to Seoul but also into the royal palace in his later days, thereby coming to get the royal command to participate in Royal medical council for curing King Sukjong of the disease. With the worsening of his health, Yu, Ie-tae passed away one year after returning home.