Abstract: This work deals with a number of commercial drugs all known in China as Pai Tou Weng (白头翁). Collected from 15 provinces and municipal districts in this country, the material on hand, consists of 16 species of different plants tearing this name. In Chinese herbals Pai Tou Weng is represented by several plants of different botanical origin, but the one mentioned in the "Pen Tsao of the Tang Dynasty" by Su-Kong should be adopted as the correct one, because his descriptions of this medicinal herb can be definitely referred to the plant Pulsatilla chinensis (Bge.) Reg. Botanical and pharmacognostical descriptions, histological studies of roots, and observations and identifications of root powders and trichomes of rootstocks are carefully made on three most important species, namely, (1) Pulsatilla ckinensis (Bge.) Reg. (Ranunculaceae), (2) Potentilla chinensis Ser. and (3) Potentilla discolor Bge. (Rosaceae), which are comparatively commonly used as remedies for amoebic dysentery in China. The distinguished pharmacognostical characteristics of each of the above-mentioned species are tabulated as follows: