A new 4,5-dioxoaporphine, named corydione, was isolated from the whole herb of Corydalis bulbosa (L.) Dc (Papaveraceae), together with dehydronantenine, (-)-stylopine, (+)-bicuculline, (-)-adlumidine, (+)-nantenine, (+)-bulbocapnine, protopine (-)-domesticine, (+)-corydine, predicentrine, oxonantenine, (+)-isoboldine and nandazurine. Glaucine and thaliporphine were detected by means of thin-layer chromatography. In addition, one minor alkaloid Cb-4, uncompletely identified, was described. The spectral data of corydione, predicentrine and nandazurine are given.