Neidan, or internal alchemy, is an array of esoteric doctrines and physical, mental, and spiritual practices that Taoist initiates use to prolong life and create an immortal spiritual body that would survive after death. Also known as Jindan, inner alchemy combines theories derived from external alchemy, correlative cosmology, the emblems of the Yijing, and medical theory, with techniques of Taoist meditation, daoyin gymnastics, and sexual hygiene.

Taoism or Daoism is a diverse tradition indigenous to China, variously characterized as both a philosophy and a religion. Taoism emphasizes living in harmony with the Tao—generally understood as being the impersonal, enigmatic process of transformation ultimately underlying reality. The concept originates in the Chinese word 道, which has numerous related meanings: possible English translations include 'way', 'road', and 'technique'. Taoist thought has informed the development of various practices within the Taoist tradition and beyond, including forms of meditation, astrology, qigong, feng shui, and internal alchemy. A common goal of Taoist practice is self-cultivation resulting in a deeper appreciation of the Tao, and thus a more harmonious existence. There are different formulations of Taoist ethics, but there is generally emphasis on virtues such as effortless action, naturalness or spontaneity, simplicity, and the three treasures of compassion, frugality, and humility. Many Taoist terms lack simple definitions and have been translated in several different ways.