Abstract:This paper reports the result of the content determination of water extract of Caulis Aristolochiae Manshuriensis. It has been found that the yellower colour of section, the richer the contents of the water extract, and the contents tend to decrease when stored for a long time or unsuitably kept. The contents ot water extract have nothing to do with the diameter or the producing area. We suggest using cold extraction to determine the contents of water extract of Caulis Aristolochiae Manshuriensis and the content should not be less than 16 percent