The structures of momordica saponins I and II, the seed saponins of Momordica cochinchinensis SPRENG. (Cucurbitaceae) have been elucidated on the basis of spectral and chemical evidence as the 3-O-β-D-galactopyranosyl (1→2)-[α-L-rhamnopyranosyl (1→3)]-β-D-glucuronopyranosido-28-O-β-D-xylopyranosyl (1→3)-β-D-glucopyranosyl (1→3)-[β-D-xylopyranosyl (1→4)]-α-L-rhamnopyranosyl (1→2)-β-D-fucopyranosides of gypsogenin and quillaic acid, respectively. I and II are contained in the seed kernels in a carboxylate form.