See also : Wikipedia:Alchemy
1.a form of chemistry and speculative philosophy practiced in the Middle Ages and the Renaissance and concerned principally with discovering methods for transmuting baser metals into gold and with finding a universal solvent and an elixir of life.
2.any magical power or process of transmuting a common substance, usually of little value, into a substance of great value.
In Daoist practice, a set of procedures and principles meant to prolong human life. In Daoism, there were two types of alchemy: "Outer Alchemy", which was the chemical production of elixirs that were meant to be eaten and "Inner Alchemy" which relied on symbolic meditation.