"Four Great Doctors in Jin and Yuan Dynasties" refers to Liu, Zhou and Zhu Zhenheng in Jin and Yuan Dynasties (A.D. 1 15- 1368). Academically, they have their own characteristics and represent four different schools. Liu advocates "fiery heat causes disease" and makes good use of cold medicine, so he is called "fire control school" or "cold cool school"; Zhang Congzheng advocated "all diseases are caused by evil" and "making good use of" sweat ","vomit "and" diarrhea "to attack evil, so it was called" attack faction "; Gaoli advocates "internal injury to the spleen and stomach, all diseases are caused by health" and makes good use of "invigorating qi and rising yang", so it is called "spleen and stomach school" or "soil-tonifying school"; Zhu Zhenheng advocated the theory of "yang is more than yin" and "mutual fire", and made good use of nourishing yin to reduce fire, so he was called "Ziyin School".