Abstract: Huang-qin is a famous drug commonly used in Chinese traditional medicine. A recent survey of this drug, however, revealed that there are seven species all known in market as "Huang-qin". Through the botanical identification of the specimens collected from 14 districts, the original plants of the drug showed that they all belong to the genus Scutellaria (Fam. Labiatae). From the phylogenetical point of view, besides S. tenax W. W. Sm. var. patentipilosa (Hand.-Mazz.) C. Y. Wu, the remaining species are all derived from the Sect. Stachymacris A. Hamit Subsect. Angustifolia Benth., viz. S. baicalensis Georgi, S. amoena C. H. Wright, S. viscidula Bge., S. rehderiana Diels, S. likiangensis Diels, S. hypericifolia Levl. etc.By means of TLC, the results indicated that all the 7 species mentioned above contain the following main active components: baicalin, baicalein and wogonin.Estimated by a quantitative method, the baicalin were as follow: 3.6～6.2% in S. baicalensis, 3.8～4.9% in S. viscidula, 3.4～4.0% in S. amoena, while the contents of baicalin were 1.7% in S. rehderiana, 2.5% in S. hypericifolia, 2.0% in S. likiangensis and 1.9% in S. tenax var. patentipilosa, respectively (cf. Tab. 2).Comparison of the dry and fresh roots of the three kinds of Huang-qin, the baicalin contents of the fresh roots were constantly higher than the dry ones.