Abstract:Through a critical study of Loulu in ancient Chinese herbals, it is concluded that the botanical origin of Loulu should be Qizhou Loulu, the dried root of Rhapontioum uniflorum of family Compositae. while the dried root of Echinops latifolius, which is also one of the species specified in Chinese Pharmacopoeia, should not be used as Louln because of its deficiency of herbal evidences and totally different chemical constituents from those of the former. It is therefore recommended the latter plant be deleted from the Chinese Pharinacopoeia.