In order to clarify the antispasmodic action of the Chinese drug Yutan (dried bear's gall) antispasmodic effect was compared in eight kinds of Yutan from different districts, and the galls of wild bear and hog. Of these, two with significant difference in the effect, the Thibet product with the strongest action and a weak one from the Tohoku district of Japan were selected and their components were separated by paper chromatography. A total of six spots were obtained from the former and nine from the latter. Ratio of contents of the corresponding components was examined and, from the correlation between this ratio and the efficacy ratio, it was concluded that the principle of the antispasmodic effect of Yutan as a whole was tauroursodeoxycholic acid. Action mechanism of the antispasmodic effect of ursodeoxycholate was examined through the dose-response curves and was found to be a papaverine-like action.