The alkaloid compositions of the roots, young shoots, and leaves of Berberis sibirica have been studied, and berberine, palmatine, columbamine, berberrubine, oxyacanthine, berbamine, 8-oxoberberine, 8-oxoberrberubine, pakistanine, and pronunciferine, and also the new base N-acetylhomoveratrylamine have been isolated. This is the first time that any of these alkaloids, except berberine, have been isolated from this plant. © 1994 Plenum Publishing Corporation.