The concept of makwon(膜原) holds great importance in the texts of Seup-yeoljobyeon(濕熱條 辨). Research on the concept was based on Seolsaengbaek(薛生白)`s medical theories organized by Wang Maengyeong(王孟英). The results are as follows. Seolsaengbaek describes makwon as half-exterior half-interior(半表半裏) of yang-myeong(陽明) and half-exterior half-interior of the body. The half-exterior half-interior in these definitions each hold a different meaning. In half-exterior half-interior of yang-myeong, it refers to its mediating function, focusing on the location of makwon as yang-myeong. In half-exterior half-interior of the body, it refers to an intersection where the pathological mechanism of damp-heat disease(seup-yeoljeung 濕熱證) begins, and also where the course of the disease changes. This is why treatment of the makwon is included in treating many damp-heat disease symptoms. The conditions derived from the original damp-heat disease can follow the designated prognosis, or follow a reversed course. Because of its intersecting role, treating the makwon can help prevent aggravation. In treatment, consideration of the healthygi(jeonggi 正氣), the bodily fluids(jinaek 津液) with an understanding of the various prognosis is crucial.