Abstract: Objective To analyze the nuclear ribosome DNA(nrDNA) internal transcribed spacer(ITS) sequences of 4 Leonurus species,and the possibility of using them for molecular authentication of the crude drugs from the genus.Methods The nrDNA ITS sequence(including ITS1,5.8S rDNA,ITS2,and partial 18S rDNA and 26S rDNA) of L.japonicus and its 3 adulterant species were amplified and sequenced,and CLUSTRAL X and MEGA software was employed for analysis.Results The variation of ITS1 and ITS2 between L.japonicus and its adulterant species ranged between 7.2% and 18.8% and between 14.2% and 27%,respectively.The phylogenic tree derived from the dendrograms based on the ITS sequence data contained some discrepancy from the traditional classification.Conclusion The nrDNA ITS sequences can be used potentially as efficient markers for identification of L.japonicus and its adulterants,and further study is needed for studying the phylogeny of Leonurus.