Tangye Principal（《汤液经法》） was first seen in Records of Art and Culture in History of Han Dynasty. At present

the mainstream understanding of the academic world is that the Tangye Principal is the source of Treatise on Cold Pathogenic and Miscellaneous Diseases（《伤寒杂病论》）and is a book of classical prescriptions. By sorting out the relationship between Treatise on Cold Pathogenic and Miscellaneous Diseases and Tangye Principal

it is believed that the Tangye Principal is not a work of classic prescriptions

nor is it the source of Treatise on Febrile Diseases. By studying the related elaboration on Tangye Principal in the pre-Qin and Han Dynasties

the author believes that Tangye Principal is a book based on diet therapy. It is believed that the "decoction" cannot be equated with the "tang liquid"

thus supporting the theory that Tangye Principal is based on diet.