The Herbal Medicine for Dietotherapy written by Meng Chang, a famous scholar, medical scientist and dieter in the Tang Dynasty, specially collects and introduces all kinds of foods with nourishing body and curative effect for people to use, so that people can get the benefits of treating diseases from their diet. Materia Medica for Dietotherapy, written more than 1 years ago, is the earliest extant monograph on dietotherapy in the world. Its contents are scattered in the comprehensive herbal books of later generations. In 187, a handwritten examination paper of this book was found in Dunhuang Grottoes in Gansu Province.