In the present study, on the isometric conditions of the rat aortic smooth muscle the vasorelaxant effect of the two polyphenol compounds 1-O-galloyl-6-Obisgalloyl-2,4-valoneil-β-D-glucose (PC-3) and 1-O-galloyl-2,3-gexahydroxydiphenoil-4,6- valoneil-β-D-glucose (PC-2), isolated from Euphorbia plant speacies (encrypted as PC-3 and PC-2) depending on their chemical structure was investigated. It was obtained that the vasorelaxant effects of PC-3 (1-O-galliol-6-O-bisgalliol-2,4-valoneil-β-D-glucose) and PC2 (1-O-galloil-2,3-hexagydroxidiphenoil-4,6-valoneil-β-D-glucose) in experiments depend on their concentration and chemical structure, as well as blockade the Ca2+ L – channel in the plasmolema of smooth muscle cells.