Abstract: To study the chemical constituents of the fruits of Polygonum orientale L., silica gel and ODS column chromatography methods were used to separate and purify the constituents. Their structures were elucidated on the basis of physicochemical properties and spectral analysis. Three compounds were identified as 28-O-β-D-glucopyranosyl-3β,7β-dihydroxy-lup-20(29)-en-28-oate (1), 5,7-dihydroxychromone (2) and naringenin (3). Compound 1 is a new triterpenoid saponin and others were isolated from the fruits of this plant for the first time.