The petroleum ether extracts from several plants have been screened on the plates with the chromogenic reagent Fast Blue B. salt. Extracts from different plant parts of Amorpha fruticosa, A. nanna, and A. canescens gave several spots with color and Rf values similar to those of Cannabis sativa extract. The major compound, amorphastilbol (1), was isolated by column chromatography, purified, and characterized by mp, elemental analysis, uv, ir, mass, prm, and cmr spectroscopy. Further information was obtained by analyzing the oxidation products of the compound. The evidence indicates that amorphastilbol is a phenolic stilbene terpenoid with a molecular formula of C24 H28 O2 and structural formula: (E,E)-2-(3',7'-dimethyl-2'-6'-octadienyl)-5-(2-phenylethenyl)-1,3-benzenediol. This is the first report of the isolation of a naturally-occurring stilbene derivative possessing a terpenoid moiety.