Abstract: The constituents of the root of the Ghinese folk medicine Wo-er-chi (Diphylleiasinensis Li) (Berberidaceae), collected in Shensi province were investigated. Three crystalline substances, podophyllotoxin, dehydropodophyllotoxin and kaempferol were isolated from the ethanol extract. These substances were identified separately by spectral analyses, chemical reactions and by the fact that no depression of mp with authentic samples was observed. The maximem yield of podophyllotoxin is 2.5%.