Abstract：From Xia, Shang, Zhou Dynasties to Han and even Middle Tang Dynasty, the system of “observing public opinion through poetry”was proposed. This idea holds that folk songs contain information of public opinion and are popular among both common people and the upper class, thus can be used to observe public opinion. The public opinion of poetry facilitates communication between rulers and common people, which is similar to the cure for stagnation in traditional Chinese medicine, both of which are based on the idea of Tongtai in The Book of Changes.

Keyword：public opinion of poetry;traditional Chinese medicine;cure for stagnation;Tongtai;