During pre-Qin and Han Dynasties

observation of pathogenesis has already been the core of diagnosis and treatment process

and a relevant system with pathogenesis differentiation as the core has been established

with"Nineteen Items of Pathogenesis"in Inner Canon of Yellow Emperor（《黄帝内经》） as a model and plenty practical examples with pathogenesis differentiation in Inner Canon of Yellow Emperor and Treatise on Cold Pathogenic and Miscellaneous Diseases（ 《伤寒杂病论》）. In Sui Dynasty

General Treatise on the Cause and Symptoms of Diseases（ 《诸病源候论》） systematically arranged the etiology

pathogenesis and symptoms of various diseases

so that clinical application of pathogenesis differentiation became convenient. During the times of the Jin and Yuan Dynasties

LIU Wansu wrote Suwen Bingji Qiyi Baoming Ji（ 《素问病机气宜保命集》） and Suwen Xuanji Yuanbingshi（ 《素问玄机原病式》）

in which he focused on pathogenesis and explained pathogenesis with"five evolutive phases and six climates factors".He supplemented the "Nineteen Items of Pathogenesis"and took it as the outline to develop the system of pathogenesis differentiation

promoting the pathogenesis differentiation system. During the period of the Ming and Qing Dynasties

the concept of pathogenesis covered a wider range. The four diagnostic methods were for pathogenesis differentiation

and treatment therapy and prescription were decided based on pathogenesis

and improved the system for treating exogenous disease based on pathogenesis differentiation. The importance of the pathogenesis in the diagnosis and treatment has become the consensus of more doctors.