An aqueous solution of a methanolic extract of the epigeal part ofVerbascum saccatum C. Koch (1.4 kg) was washed with organic solvents and chromatographed on columns of alumina, polyamide, and silica gel, leading to the isolation of 3.6 g of a new iridoid glycoside — saccatoside (I) — in the form of an amorphous substance with [α] D 20 −200±2.5° (c 0.2; methanol). The structure of (I), corresponding to 6-O-(2″-p-coumaroyl-α-L-rhamnopyranosyl)catalpol, was shown on the basis of the spectral characteristics of (I) and of its octaacetyl derivative (II) (mp 99°C, [α] D 20 −150±2.5°) and alkaline hydrolysis to 6-O-α-L-rhamopyranosylcatalpol (III). In addition to (I), aucubin and (III) were detected chromatographically in the iridoid fraction. Details of the IR, NMR, and13C spectra of (I) and (II) and of the mass spectrum of (II) are given.