Objective : Two famous medical doctors, Yoo Itae(以泰, 爾泰) and Riu Euitae(義泰), have been well known in academic world and public in Sancheong-gun. Yoo Itae is the progenitor of Majinhak which is the therapy for measles, he wrote a "Majinpyun" as the first book of therapy for measles in Chosun. Riu Euitae, meanwhile, is a fictional medical doctor and a teacher of Heo Jun who became real without confirmation of historical truths by Roh Jeongwoo who heard about a name, Yoo Itae. Roh's assertion was quoted in the report of literatures, papers, novel, and telecast without verification. His assertion is exposed in novel and media and it has seriously distorted the history. The purpose of this study is to rectify the historical distortion. Methods : Various references study was performed. Confirmed a family tree, birth and death year, birthplace, sepulture, words on a tombstone, writing, collections of works anthology and the existence of keepsake. Investigated records of royal family, Sancheong-gun papers, Sancheong Hyanggyo papers, Dongyuhagan, Chosun Hanryuseungram and the record of Sawoo Munjip(anthology). Analyzed Roh Jungwoo's conversation that tells Riu Euitae is a teacher of Heo Jun and contents of an encyclopedia. Listened to testimony of descendants and assertions of historian in rural area. Verified voice recording on books taken from at birthplace and the space of activity. Results : Yoo Itae is well shown in various records and medical writing books, whereas Riu Euitae does not. Riu Euitae is not a real person in the history. Roh Jeongwoo who asserts Riu Euitae is a teacher of Heo Jun admits his mistake. But, the encyclopedia record describing Riu Euitae is a teacher of Heo Jun, government official at Sancheong district office, historians in rural area, historians in rural area who made a family shrine, gravestone, a statue, memorial, historic site of Riu Euitae on Jinju Rui could not suggest any evidences for the existence of Riu Euitae and for record Riu Euitae is a teacher of Heo Jun. Conclusion : Riu Euitae is neither a real person in the history nor a teacher of Heo Jun. Riu Euitae came from pronunciation confusion between 'I' and 'Eui' in Kyungsang province. Riu Euitae is Yoo Itae on Geochang Yoo who was a medical doctor of King, Sukjeong and wrote medical books including , , .