Chemical constituents of Corydalis pallida PERS. var. tenuis YATABE were studied. A new natural alkaloid, d-tetrahydrocorysamine was isolated from the whole herb of this plant, together with dihydrosanguinarine, oxysanguinarine, protopine, l-tetrahydropalmatine, d-corydaline, capaurimine, capaurine, capauridine, l-scoulerine, the so-called l-corydalmine, ginnol, and trans-3-ethylidene-2-pyrrolidone. From the quaternary base fraction, sanguinarine, corysamine, coptisine, and dehydrocorydaline were detected by means of a thin-layer chromatography. At the same time, the structure of capaurimine was revised to 1.10-dihydroxy-2,3,9-trimethoxydibenzo[a,g]quinolizidine (V) on the basis of nucler magnetic resonance and mass spectra.