Two new saponins, β- D-glucopyranosyl 3- O[ O-β D-xylopyranosyl-(1→3)-O-(β- D-glucopyranosyluronic acid)]oleanolate ( 1) and 3- O-[ O-β- D-xylopyranosyl-(1→3)-O-(β-D-glucopyranosyluronic acid)]oleanolic acid ( 2), have been isolated from the tubers of Talinum tenuissimum. The structures have been established mainly by 13C-NMR and FAB-MS. The monodesmosidic saponin 2 exhibits very strong molluscicidal activity against the schistosomiasis-transmitting snail Biomphalaria glabrata.