A chemical examination of polyphenols in Euphorbia helioscopia L. (Euphorbiaceae) has led to the isolation of four new hydrozable tannins named helioscopinins A (10) and B (9), and helioscopins A (11) and B (12), together with eight known tannins (1-8). On the basis of chemical and spectroscopic evidence, the structures of compounds 9-12 were established as 1, 6-(S)-hexahydroxydiphenoyl-3-O-galloyl-β-D-glucose, 1, 6-(S)-hexahydroxydiphenoyl-2, 4-(S)-dehydrohexahydroxydiphenoyl-3-O-galloyl-β-D-glucose, 1, 6-(S)-hexahydroxydiphenoyl-2, 4-(R)-elaeocarpusionoyl-3-O-galloyl-β-D-glucose and 1, 3, 6-tri-O-galloyl-2, 4-(R)-elaeocarpusinoyl-β-D-glucose, respectively.