“Efficacy determines degree” is derived from Treatise on Febrile Diseases. It is a method of controlling the overall dosage based on the pharmaceutical effect. In clinical practice, the severity of the disease, the nature and flavor of Chinese medicine and the degree of tolerance of the human body are different, so the dosage cannot be generalized. The dosage should be grasped macroscopically according to the exact reaction of the patient after taking the medicine to achieve the purpose of individualized treatment. Zhongjing attached great importance to observing the patient's different reactions after taking prescription. The authors have combed the relevant discussion in Treatise on Febrile Diseases and Synopsis of Golden Chamber comprehensively and the relevant discussion can be a basis for the efficacy evaluation and controlling dosage of classical formula in clinical practice. It is intended to draw inferences from other cases and enlighten the thinking of medication in clinical practice, so as to inherit and carry forward Zhongjing academic better.