Shennong's Classic of Materia Medica also discusses the basic pharmacological theories such as "monarch, minister, assistant", "seven emotions" and "four qi and five flavors", as well as the collection time, processing, storage, dosage form, medication principles and methods of drugs. For example, the book says, "If poison cures a disease, the millet will start first and the disease will stop." . That is to say, when using toxic drugs to treat diseases, the initial dose should be small, like the size of millet grains. Stop taking medicine immediately after the illness is cured. It is also mentioned in the book that the treatment should be guided by the situation, that is, to find out the clues of disease changes for treatment, which embodies the principle that treatment must be based on needs. These theories have always been the guiding ideology of traditional Chinese medicine. Therefore, Shennong's Classic of Materia Medica is listed as one of the four classic works of traditional Chinese medicine, which has become the standard for later doctors to learn. Compendium of Materia Medica is a masterpiece of oriental pharmacy and the crystallization of Li Shizhen's painstaking efforts for more than 30 years in Ming Dynasty. The book * * *1.9000 words, recorded drugs 1.892 kinds, divided into 60 categories. Among them, Li Shizhen added 374 new drugs. There are more than 1 100 drawings and more than 1 1000 prescriptions. It is a summary of China's pharmacology for thousands of years. This Pharmacopoeia, no matter from its strict scientific classification, or from the number of drugs it contains and the fluent and vivid writing, far exceeds any ancient herbal works.