Four new alkaloids, named 1-(4'-methylpyridazin-5'-yl)butane-1,2,3,4-tetraol (1), 3,9-dimethyl-5-nitropyrido[3,2,1-ij]quinazoline-1,7-dione (2), N,N-di(1-imine-propanyl)propionamidine (3), and 2,7-bis(isopropylimino)-2H,7H-dicyclopentacyclooctene-4,9-diol (4), were isolated from the rhizomes of Ligularia duciformis. Their structures were elucidated by spectral analysis.