The ITS2 barcode was used to identify Polygoni Orientalis Fructus and its adulterants in this study.Methods:For the accuracy of the identification，a total of 71 samples from Polygoni Orientalis Fructus and its adulterants were collected.The DNA was extracted from the samples and the ITS2 regions were amplified and sequenced.The sequences were then assessed and assembled using the CodonCode Aligner.The genetic distances and variable sites of ITS2 region were analyzed using MEGA after sequence alignment.Nearest distance and phylogenetic tree(NJ-tree)methods were used to test the identification efficiency of the ITS2 barcode.Results:The intraspecific genetic distances of Polygonum orientale were 0~0.0124，while the interspecific genetic distances between P.orientale and its adulterants were 0.0334~0.0508，0.0688~0.0875 and 0.0379~0.0467，respectively.The maximum intraspecific genetic distance of P.orientale was lower than the minimum interspecific genetic distance between P.orientale and its adulterants，which showed that ITS2 barcode could discriminate P.orientale and its adulterants accurately.Besides，the NJ tree based on ITS2 sequences supported that P.orientale and its adulterants can be easily differentiated.Conclusion:The ITS2 barcode is an effective tool for the identification of P.orientale and its adulterants.Our study may provide a new technique to ensure the production feeding security of traditional Chinese medicine.