Abstract: Clerodendrin, a flavone glycoside with the structure of apigenin7-U-digiucuronide, has been isolated once more from the leaves of Clerodendron trichotomum Thunb. by a method of precipitation which is different from that used in the early research. Its complete structure, apigenin-7-O-β-D-glucuronopyranosyl (1→2)-β-D-glucuronopyranoside, is elucidated by the combined application of UV, IR, NMR and MS. The glycosylation shifts of the sugar moiety of clerodendrin in ¹³C NMR show that two glucuronic acids with the β-anomeric carbon are linked to each other in the form of 1→2.Clerodendrin showed a hypotensive activity in the rat by measurement of the tail volume pressure in preliminary pharmacological tests.