Two new glycosidic acids, quamoclinic acids G and H, were isolated from the glycosidic acid fraction afforded by alkaline hydrolysis of the ether-insoluble resin glycoside (convolvulin) fraction from the seeds of Quamoclit pennata BOJER. Both compounds are the first examples of bisdesmosides of glycosidic acid having the sugar linkages at C-3 of 3,11-dihydroxytetradecanoic acid (ipurolic acid) as well as at its C-11.