In the stem and roots of Thalictrum javanicum Bl. six quaternary alkaloids, palmatine, berberine, columbamine, jatrorrhizine, magnoflorine and demethylene berberine were isolated and identified. The structure of the new alkaloid demethylene berberine was proved by means of uv, ir, nmr and mass spectrometry and by its chemical conversion into palmatine. © 1983, American Chemical Society. All rights reserved.