Taoist elixir is the noun of ancient alchemy in China. Including Waidan and Neidan. Waidan is a yellow medicinal gold (Huandan) made of cinnabar (red mercuric sulfide), lead, sulfur and other raw materials. Its finished product is called the elixir. Taoism believes that people can become immortals and live forever after eating. The alchemy before Tang Dynasty mostly refers to external alchemy. After the Tang and Song Dynasties, it mostly refers to inner alchemy, that is, taking the human body as the furnace and the essence in the body as the medicine. Taoism believes that essence, qi and spirit can be condensed into sacred fetuses and turned into immortals.

Initially, it was a term for external alchemy. It refers to the elixir extracted by an alchemist from some mineral raw materials, also known as "elixir", which is believed to be immortal after taking it. Inner alchemy refers to inner alchemy by borrowing the word at that time.