Objective: To establish a convenient and effective method for the identification of Gynostemma and Cayratia japonica . Method: Eight species, including Gynostemm pentaphyllum , G. pentagynum , G. cardiospermum , G. longipe , G. yixingense , G. laxiflontm, G. guangxiense and C. japonica were investigated through PCR - RFLP of six chloroplast DNA fragments. The six gene fragments were digested by six restriction endonuclease respectively, including Taq I , Hpa ]I , EcoR I , Rsa I , Hha ] , Hind Ill. Re- suit: Seven species of Gynostemma and th...