High-performance liquid chromatographic procedure was established for the quantitative method of flavonoids in Scutellaria root ("Huangqin", the root of Scutellaria baicalensis GEORGI). Eleven flavonoids, baicalein (I), baicalin (II), baicalein 7-O-glucoside (III), oroxylin A (IV), oroxylin A 7-O-glucuronide (V), wogonin (VI), wogonin 7-O-glucuronide (VII), chrysin (VIII), skullcapflavone II (IX), 5, 7, 2', 6'-tetrahydroxyflavanone (X) and dihydrooroxylin A (XI), were separated by the combined use of both operating conditions of 1 and 2 shown in Fig. 2 and 3, respectively. This method is considered to be useful for the chemical evaluation of commercially available Scutellaria root.