The phenomenon of a syndrome caused by multiple causes is a clinical phenomenon that the same syndrome can be triggered by different etiologies or pathological factors through changes of some identical pathological links.It is uncommon in clinical practice，and it has profound connotation and significance.Based on the further discussion of Baihu Jia Renshen tang，the authors pointed out that the essence of the phenomenon of a syndrome caused by multiple causes still lies in the transformation and evolution of the etiology，and believed that the in-depth analysis of this phenomenon can improve the theory of Chinese medicine and the level of differentiation and treatment and that it can at the same time help to uncover the essence of the syndrome，thus providing certain enlightening significance for clinical differentiation.