An entheogen in the strict sense, is a psychoactive substance used in a religious, shamanic, or spiritual context. Historically, entheogens were mostly derived from plant sources and have been used in a variety of traditional religious contexts. With the advent of organic chemistry, there now exist many synthetic substances with similar psychoactive properties, many derived from these plants. Entheogens can supplement many diverse practices for healing, transcendence, and revelation, including: meditation, psychonautics, art projects, and psychedelic therapy.