Diarylheptanoids, (5S)-1,7-bis-(3,4-dihydroxyphenyl)-5-hydroxyheptane-3-one (1, hirsutanonol), $(5S)-1,7-bis-(3,4-dihydroxyphenyl)-heptane-3-one-5-O-{eta}-D-xylopyranoside (2, oregonin)$, $(5R)-1,7-bis-(3,4-dihydroxyphenyl)-heptane-5-O-{eta}-D-xylopyranoside (3)$, and $(5R)-1,7-bis-(3,4-dihydroxyphenyl)-heptane-5-O-{eta}$-D-glucopyranoisde$ (4) were isolated from the leaves of Alnus hirsuta Trucz. The structures of these compounds were identified based on the spectral and physicochemical data.