Chinese crude drug 'Se Sin'(細辛)has been used to cure headache, cough and expectorant. To the botanical origin of 'Se Sin', Zhong-yao-zhi(中葯志) reported Asarum heterotropoides var. mandshuricum. A. sieboldii and A. sieboldii var. seoulensis, and Zhong-yao-da-ci-dian(中葯大辭典) reported Asarum heterotropoides var. mandshuricum and A. sieboldii of Aristolochiaceae. In Korea, this crude drug has been used as a Korean folk remedy for tothache and aromatic. The botanical origin of 'Se Sin' is considered to be Asarum species of Aristolochoaceae. But there has no pharmacognostical confirmation on it. To clarify the botanical origin of 'Se Sin', we studied on the anatomical characteristics of Asarum species growing wildly in Korea i.e. A. maculatum, A. sieboldii, A. sieboldii var. seoulensis, and of 'Se Sin' from Korea on Korean market. Through our studies, the botanical origin of 'Se Sin' from Korea was proved to be whole plant of Asarum sieboldii and A. sieboldii var. seoulensis.