The Development Process of External Alchemy

External alchemy first appeared in the Western Han Dynasty. In the second year of Yuanguang in the Western Han Dynasty (133 BC), the alchemist Li Shaojun asked Emperor Wu to "offer sacrifices to the kitchen god" and "summon spiritual beings", and to transform cinnabar into gold "to make eating utensils". Emperor Wu followed his advice, "personally offered sacrifices to the kitchen god", and "engaged in transforming cinnabar and other medicinal ingredients into gold", indicating the emergence of external alchemy.

During the Eastern Han Dynasty, Wei Boyang wrote The Zhouyi Cantongqi (The Kinship of the Three, Based on the Book of Changes), which is revered by Taoism as the "King of Alchemical Scriptures". Around this time, it is said that Zhang Ling produced The Nine Tripod Alchemical Methods (i.e., the existing The Yellow Emperor's Nine Tripod Divine Elixir Scripture), and Yin Changsheng produced The Supreme Pure Gold Liquid Divine Elixir Formula. By then, external alchemy had become an important cultivation technique in Taoism.

During the Wei, Jin, Southern and Northern Dynasties, external alchemy continued to develop. Ge Hong received three volumes of The Supreme Pure Alchemical Scripture, one volume of The Nine Tripod Alchemical Scripture, and one volume of The Gold Liquid Alchemical Scripture from Zheng Yin. In his later years, he practiced alchemy in Luofu Mountain. He believed that "the way to longevity does not lie in offering sacrifices to ghosts and gods, nor in daoyin (guidance of qi) and body stretching; the key to ascending to immortality lies in divine elixirs". The chapters such as Golden Elixirs, Yellow and White (referring to the transmutation of metals), and Immortal Medicines in Baopuzi Inner Chapters contain as many as forty to fifty alchemical methods.

External alchemy reached its peak in the Tang Dynasty. From Emperor Taizong to Emperor Xizong, most emperors liked to summon Taoists to concoct elixirs or took elixirs themselves. There was no lack of civil and military officials who were fond of this technique in each generation. More alchemists and alchemical books emerged during this period. Sun Simiao's medical works Qianjin Fang (Thousand Golden Prescriptions) and Qianjin Yifang (Supplements to the Thousand Golden Prescriptions) contain many alchemical methods, and his specialized work on external alchemy The Essential Secrets of the Great Pure Alchemical Scripture still exists today. The methods of making elixirs in the Tang Dynasty were more advanced than before, and alchemical tools were also improved.

With the development of external alchemy, the number of people who died from taking elixirs increased day by day. Zhao Yi of the Qing Dynasty recorded in Notes on Twenty-Two Histories that as many as six Tang emperors died from taking elixirs (there are also claims of five or four), and even more ministers died from it. As a result, people from both the court and the common people criticized it, and those who took elixirs, including alchemist Taoists, gradually became skeptical. Therefore, external alchemy gradually declined after the Tang Dynasty. Both the Southern and Northern Schools of the Quanzhen Taoism in the Southern Song Dynasty advocated internal alchemy cultivation, so external alchemy declined further.