Extensive isolation work on the n-BuOH-soluble fraction obtained from the stem and root barks of Ulmus pumila L. afforded five  compounds. Four were identified as (+)-catechin 1, (+)-catechin 7-O-gallate 2, (+)-catechin-5-O-b-D-apiofuranoside 3, and (+)-catechin-7-O-b-D-apiofuranoside 4. The structures of the remaining new compound was elucidated to be, (+)-catechin-7-O-gallate-5-O-(5``-trans-caffeoyl)-b-D-apiofuranoside-3-O-b-D-apiofuranosyl-(1®2)-glucopyranoside 5, by chemical and spectroscopic analysis. The ethanolic and n-butanol extracts and the isolated compounds (1-5) were tested for their antioxidant activity using DPPH radical scavenging assay, xanthine oxidase-induced generation of superoxide radical and lipid peroxidation assay by thiobarbituric acid-reactive substances (TBARS) method using rat tissue homogenates.