在东汉时期，炼丹术蓬勃发展，其理论丰富、技术精湛，设备先进。这个时期的炼丹大家中，有一人名声远扬，那就是狐刚子。他的本名是狐丘，又称狐罡子，他生活在东汉末年，是一位著名的炼丹高手。在他的一生中，他创作了许多著作，如《五金粉图诀》、《狐刚子万金诀》、《出金矿图录》、《河东经》、《玄珠经》和《金石还丹术》，这些作品对于后世产生了深远影响。
fox ganzi's works, such as "five gold powder formula" and "out of gold mine records", are the earliest to record the use of "fire below and condensation above" method to refine cinnabar from realgar; application of yellow lime, collection and extraction of the essence from stone gall, which is a chemical reaction and experiment with sulfuric acid. At the same time, he also recorded the method of producing "xuanhuang" (a mixture of lead dan and mercuric oxide). In terms of technology for refining precious metals such as gold and silver, fox ganzi first proposed and applied the methods of "graying kiln" and "blowing gray". These methods had a profound impact on later generations.
In Chinese history books on lead chemistry, his method known as "nine turns lead dan law", is still passed down today as one of the earliest methods for producing red mercury. It can be said that fox ganzi was not only an important figure in eastern Han period but also made great contributions to alchemy through experimentation with new techniques.
