The isolation and identification of eleven crystalline components from the aerial part of Cynanchum taiwanianum Yamazaki (Asclepiadaceae) are described. Their structures were determined on the basis of spectral evidence and chemical transformation. Besides caffeic acid.ri-amyrin, and methyl phaeophorbide a, the isolated flavonoid components are classified into two groups, i.e. kaernpferol derivatives (kaempferol, astragalin, afzelin, trifolin) and quercetin derivatives (quercetin, isoquercitrin, quercitrin, hyperin). H lllUCO$yl rI1amnosyl galaclosyl J K