Dihuang(Rehmannia glutinosa) has been used as a traditional Chinese herbal medicine for thousands of years in China, which is mainly distributed in Henan, Hebei, Shaanxi and Shanxi Provinces. It mainly contains iridoids, ionones, phenylethanoid glycosides, triterpenoids, flavonoids, and saccharides, which has significant effects on human blood system, cardiovascular and cerebrovascular system, central nervous system and immune system. In recent years, with the development of innovative methods for separation and anal., the modern science and technol. and pharmacol. methods were applied to study the chem. constituents and pharmacol. action of R. glutinosa. More and more chem. components in R. glutinosa have been discovered, and its pharmacol. actions have been further improved by development. Furthermore, the clin. application scope of R. glutinosa has been expanded year by year, which has aroused the keen attention of domestic and foreign scientific research workers. In this paper, the chem. constituents and pharmacol. actions of R. glutinosa were summarized, in order to provide some basis for its further utilization and modernization.