Rhubarb is one of the important traditional Chinese medicines, which has many functions, such as dispersing internal heat, clearing away heat and toxic materials, promoting blood circulation and removing blood stasis. Its chemical composition is complex, including free hydroxyanthraquinone, anthracene glycoside, glucoside and tannin, among which anthracene glycoside has the highest content and a small amount of rhein. It is generally believed that rhein contains rhein. In addition, it also contains resins, carbohydrates and organic acids.

The separation process of free hydroxyanthraquinone in rhubarb is as follows: