Grass rhizome, also known as thatch, white thatch and cogongrass rhizome, is a perennial herb of Gramineae. Widely distributed in temperate and tropical regions of Asia, Europe and Africa. It is distributed in most areas of China. Like shade tolerance and drought tolerance, most of them are born on roadsides and grasslands. It contains a lot of sucrose, glucose, a small amount of fructose, xylose, citric acid, oxalic acid, malic acid and so on. It also contains 2 1% starch.