Five known flavonoids were isolated from the ethyl acetate soluble fraction of aqueous extract of T. emetica whole seeds. On the basis of 1D and 2D-NMR experiments and MS data analyses, these compounds were identified as naringenin (B), taxifolin 4’-O-β-D-glucopyranoside (C), elephantorrhizol (D), catechin 3-O-β-D-glucopyranoside (E) and eriodictyol 3-O-β-D-glucopyranoside (F). DPPH radical scavenging activity was used to estimate the antioxidant capacity of each of these compounds. The result shows that elephantorrhizol has stronger DPPH scavenging activity than other isolated flavonoids.