Separation of the basic fraction from Corydalis ochotensis (Turcz.) afforded four new alkaloids [yenhusomine (5), yenhusomidine (9), corytenchine (12), and corytenchirine (21)] together with the known alkaloids, protopine, ochotensimine, and adlumidine. The identification of the new alkaloids is described. Didehydrocheilantifoline was also isolated, from a quaternary base fraction.