Background: Leonurine is a the aerial part of Leonurus japonicus Houttuyn, which has been used as a traditional medicines and is registered in the Korean Pharmacopoeia.Methods and Results:In the present study we performed a heavy metals and thin layer chromatography and measured loss on drying, as well as the contents of total ash, acid-insoluble ash, ethanol soluble compounds, and leonurine, using 15 domestically collected L. japonicus samples. The methods were performed according to the ‘crude drugs test of the general test, processes and apparatus’, published by MFDS, Korea (2014). The purity test (heavy metals) indicated that levels of Pb and Hg were 0.35 - 3.64, and 0.001 ppm, respectively, whereas the levels of As and Cd were undetectable, and stachydrine was identified by thin layer chromatography (Rf : 0.15). We found that 5.93 - 10.62% (average: 8.58 ± 1.8%) of the sample mass was lost during drying, and the contents of total ash, acid-insoluble ash, ethanol soluble compounds, and leonurine were 7.87 - 10.84% (average: 9.62 ± 0.82%), 0.99 - 1.76% (average: 1.38 ± 0.24%), 16.70 - 23.11% (average: 19.49 ± 2.14%) and 0.04 - 0.17% (average: 0.11 ± 0.04%) respectively. In addition, HPLC profiling detected leonurine (5.94 min), rutin (16.43 min) and myricetin (26.78 min).Conclusions:We hope that this the rusult of the present study will contribute to the standardization and quality control of Korean herbal medicines.