From the dried flower-buds of Panax ginseng C.A. Meyer, a new minor dammarane-type triterpene saponin named ginsenoside III together with nine known saponins was isolated. On the basis of spectral and chemical evidence, the structure of the new saponin was elucidated as 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-20-O-beta- D-glucopyranosyl-3 beta,12 beta,20(S)-trihydroxy-dammar-25-en-24-one.