An alchemist is divided into inner Dan and outer Dan. Inner alchemy was developed on the basis of Taoism. China pursues immortality through Taoism, mainly practicing inner alchemy, which has a certain scientific health preserving function. Waidan is not pseudoscience gunpowder, but was unintentionally refined and invented by Taoist priests in Tang Dynasty, which was widely used in Song Dynasty. In addition, a Taoist priest accidentally put an alchemist into soybean milk when he was alchemizing, so he invented tofu. In addition, the doctor also refined many Dan with alchemy, such as Wushi powder in Tang Dynasty.

Li, a modern chemist in China, and Joseph Needham, the author of History of Science and Technology in China, both think that alchemy is the basis of China chemistry, and the academic circles also respect Ge Hong as the pioneer of China positivism. So it is not pseudoscience, but imperfect science.