Four diarylheptanoids oregonin, hirsutanonol, 1,7-bis- (3,4-dihydroxyphenyl)-heptane-5-O-$eta$-D-xylopyanoside and 1,7-bis-(3,4-dihydroxyphenyl)-heptane-5-0-$eta$-D-glucopyranoside isolated from Alnus hirsuta were evaluated for their antioxidative effects with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and lipid peroxidation generation system mediated by addition of $H_2O$$_2$and/or Fe$^{2+}$ to rat liver homogenate. All these diarylheptanoids showed significant inhibitory activities against the DPPH radical and demonstrated strong activities in preventing the lipid peroxidation induced by $H_2O$$_2$.>.