As a continuing study of chemical characterization of crude drug processing, we have been analyzing the chemical constituents in licorice roots before and after processing. At first, we analyzed chemical constituents in licorice roots of various origins. Next, we have developed the HPLC analytical method, by which saponins and flavonoids, major constituents in various licorice roots, were determined simultaneously in a quantitative manner. In this paper, by means of the HPLC analytical method, chemical constituents in licorice roots, processed and unprocessed, were determined. It was found that nonglycosidic flavonoid constituents were mostly lost while root bark removing, whereas, in roasted licorice roots, sugar chains in the saponin and glycosidic flavonoid constituents were hydrolyzed stepwise during roasting through hydrothermolysis.