The known substances l-α-canadine methiodide, β-homochelidonine, chelerythrine, isocorydine methiodide (a new alkaloid), lupeol, and hesperidin have been isolated from both Z. brachyacanthum F. Muell. and Z. veneficum F. M. Bail. and it is suggested that these two species are identical. From Z. suberosum C.T. White the recently discovered alkaloid, canthin-6-one, was isolated.