Three flavonoid glycosides have been isolated from the aerial part of Armoracia rusticana P. (Cruciferae) in Korea and identified by means of spectral analysis as $kaempferol-3-O-{eta}-D-xylofuranoside(l)$, $kaempferol-3-O-{eta}-D-galactopyranoside(2)$ and $kaempferol-3-O-{eta}-D-xylofuranosyl(1 ightarrow2)-b{eta}-D-galactopyranoside(3)$. When 1 mg/ml of the methanol extract from the aerial part of this plant was added, lipid peroxide formation in the bromobenzene-treated rat liver decreased by 64%. Among the components isolated from title plant, compounds 2 and 3 reduced the formation of lipid peroxide by 16% and 39% respectively at the concentration of ${10}^{-1}$ mg/ml.