The art of using formulae in Traditional Chinese herbal medicine has undergone significant changes through the centuries. Starting out as fairly crude and simple portions, formulae have developed into sophisticated therapeutic tools. Through the ages there are many outstanding influential figures and books on literature of herbal formulae, but here we limit ourselves to the most important ones.

The earliest compilation of formulae in China, Wu Shi Er Bing Fang dates back to the end of the 3rd century, BC The text records 240 kinds of herbs and over 300 formulae, but they are quite crude and simple. The earliest existing Chinese Materia Medica text, Shen Nong Ben Cao Jing, states that the combination of different drugs has both therapeutic effects and limits side effects, and links dosages in different forms to specific indications.

By the time Huang Di Nei Jing was compiled, now estimated between 475 BC and the 1st or 2nd century AD, the theoretical foundations of TCM were in place. Thirteen formulae are described and the text clearly names the different dosage forms as there are decoction, pill, spirit, etc. showing that the practice of formulae started. The true ancestor of all writers of formulae is Zhang Zhong-Jing, who inherited and summarized the experiences of previous ages. In his books Shang Han Lun and Jin Gui Yao Lue, compiled during the early 3rd century AD, 113 herbs and 265 formulae are described respectively. Each of the formulae is given a name, and the dosage and method of preparation of the herbs are specifically indicated. All the formulae are elegantly and strictly formulated and based on a more advanced therapeutic system. Zhang established the principle of " treatment according to the Differentiation of Patterns" (Bian Zheng Lun Zhi). These books are a milestone and have had a tremendous influence on Chinese Medicine up to the present day. During the Eastern Jin dynasty (317~420 AD), Ge Hong wrote the most important compilation of formulae of that time; Bei Ji Zhou Hou Fang (Emergency Formulae to Keep Up One's Sleeve). This book features the use of simple and effective formulae for emergencies. Sun Si-Miao (580~682 AD), the most outstanding medical figure in the Tang dynasty (618~907 AD), compiled Bei Ji Qian Jin Yao Fang, and Qian Jin Yi Fang. Systematically summarizing the medical achievements before the Tang dynasty, Sun first used the theory of five Zang- and six Fu-organs. More than 3,500 formulae are prescribed in his books, and many of them are still in use. Another influential figure in the 8th century was Wang Tao. As secretary of the imperial library, Wang was able to read all the collections and compiled Wai Tai Bi Yao (752 AD), which is based on previously published Chinese works as well as on some foreign texts. Moreover, he classified the formulae according to the type of disorder they were designed to treat.During the northern Song dynasty (960~1127 AD) a state dispensary was established and the first official formulae text, Tai Ping Hui Min He Ji Ju Fang (Imperial Grace Formulae of Tai Ping Era) was published under imperial auspices. Compiled between 976~997 AD, this book contains 16,834 entries. During the Jin (1115~1233 AD) and Yuan (1234~1369 AD) dynasties, several schools of thought emerged, represented by four great medical figures. They were Liu's Cooling School (Han Liang Pai), Zhang's Purging School (Gong Xia Pai), Li's Earth-tonifying School (Bu Tu Pai), and Zhu's Yin-nourishing School (Zi Yin Pai). Each of these schools created new research methods and made significant contributions to the study of formulae. Also countless books of formulae were published during this period.

During the Ming dynasty (1368~1644 AD), the notable books on formulae are Jing-Yue Quan Shu and Xing Fang Ba Zheng, which were written by Zhang Jing-Yue who lived in the early 17th century. Summarizing almost all the contents of books on formulae published before the 15th century AD, the book Pu Ji Fang, compiled in 1406 AD and containing 61,739 formulae, is the biggest text existent in China. The late 17th century scholar, Wang Ang, is another influential figure in Traditional Chinese medicine. His book Yi Fang Ji Jie became very popular to practitioners because of its practicality and easy-toapply knowledge. During the Qing dynasty (1644~1911 AD), the most important achievement of Traditional Chinese Medicine was probably the appearance of the Warm-febrile Disease School. Since practitioners were dealing with many epidemics that swept through China, they developed new ideas and formulae corresponding to new diseases. They believed these new diseases were due to Warmth or Heat instead of Cold, which had always been emphasized since the time of Zhang Zhong-Jing. The most two important representatives of this new school of practice were Ye Tian-Shi, the early 18th century physician, and Wu Ju-Tong, the late 18th century physician. The two of them made valuable contributions by developing the system of differentiation of Four Stages (Wei,Qi,Ying and Xue) and the Triple Burner (San Jiao) system of diagnosis respectively. Many formulae designed during this period are still in use today and the achievements were more than sufficient to match those of the Tang dynasty and onward. In modern time, traditional Chinese formula-writing has made new achievements in both theory and practice. Classical formulae do have more extensive applications. Thanks to modern techniques and research methods, quite some new effective formulae and new forms have come into practice