The following nine known alkaloids have been isolated from Corydalis nobilis Pers.—protopine, cryptopine, d- and dl-tetrahydro-palmatine, stylopine, d-isocorypalmine, corytuberine, bicuculline, and corlumine. In addition, three as yet uncharacterized bases have been obtained. Alkaloid F54 and alkaloid F55 are phenolic and the former may be represented by C19H23O5N containing two methoxyl groups. Alkaloid F53 is non-phenolic and analyses indicate C17H17O4N.