A phytochemical study of Alnus mandshurica (Callier) Hand.-Mazz. (dried stem bark) led to the isolation of 28 compounds, including twelve simple phenols and simple phenol glycosides (1-12), 1 - 12 ), eleven flavonoids (13-23), 13 - 23 ), among them, compounds 13, 15, 17, 18, and 23 are flavan-3-ols compounds, two coumarins (24 24 and 25 ), one diarylheptanoid (26), 26 ), one lupine triterpenoid (27), 27 ), one sterol (28). 28 ). The structures of these isolated compounds were identified using NMR spectroscopy (1H 1 H and 13 C) by comparison with previously reported data. Compounds 2 , 5 - 14 , 18 , 20 , 22 , 25-27 - 27 were isolated from A. mandshurica for the first time. The chemotaxonomic significance of the isolates was also discussed.