Abstract: As stated previously the most widely used Pai-ch'ien is obtained from Cynanchum stauntoni (Dcne.)Hand.-Mazz.and C.glaucescens(Dcne.)Hand.-Mazz.,and Pai-wei obtaincd from C. alratum Bge.and C.versicolor Bge.,all belong to the family Asclepiadaceae.In this paper,detailed macrospopical and microscopical descriptions of the commercial drugs derived from these four plants are given,while the commercial samples of Pai-chien and Pai-wei derived from the other eleven plants,namely,Cynanchum amplexicaule Hemsl.,C.japonicum Morr.et Dcne.,Cynanchum sp., Pycnostdma paniculatum K.Sch.,Gerbera piloselloides Cass.,Melandryum lankongense Hand.- Mazz.,Asparagus schoberioldes Kunth.,Asparagus pallasii Printz.,Asparagus officinalis L.,Aspa- ragus Oligoclonus Maxim.,Iris dichotoma Pall.,and a recently collected species Disporum sessile Don,used as Pai-wei in Szechuan,may be regarded as substitutes and adulterants.Only their macro- seopical characters are described. The differences in macroscopical and/or microscopical characters between the above sixteen commercial samples of different botanical origin are discussed together with a key of identification.