Histochemical studies were performed on the distribution of bioactive flavones, baicalein, baincalin, wogonin and wogonin 7-O-glucuronide, in various parts and tissues of Scutellariae Radix and cultivated Scutellaria baicalensis (Labiatae) root. By means of high-performance liquid chromatography, it has been clarified that the flavone glucuronides are mainly distributed in the cortex, phloem and xylem of the root, and the aglycones are present in the outer periderm at high concentrations. It has been found that Scutellariae Radix from China is morphologically different from the drugs from Japan, Korea and North Korea.
