When Li Shizhen was practicing medicine and reading medical books, he found many mistakes in the ancient pharmacology book Materia Medica. So he decided to rewrite a new book on pharmacology. In the thirty-first year of Jiajing since Ming Dynasty (1552), Li Shizhen began to compile the vast project Compendium of Materia Medica. He visited famous doctors all over the world and traveled all over Shan Ye. With the help of woodcutters, drug farmers, hunters and fishermen, he observed and collected drug specimens and consulted more than 800 kinds of ancient books. After 27 years' efforts, 1578 finally completed this masterpiece of pharmacology. This year, Li Shizhen was 6 1 year old.
Compendium of Materia Medica consists of 52 volumes, including 1892 kinds of drugs, including 374 kinds of new drugs, and collected prescriptions 1 1096 pieces. The book also draws 1 1 1 beautiful illustrations. Compendium of Materia Medica has not only made great achievements in pharmacology, but also made outstanding contributions in chemistry, geology and astronomy. Compendium of Materia Medica is not only a masterpiece of pharmacology by China, but also an encyclopedia of ancient China.