Chromatographic procedures (HPLC, GC-MS) are outlined in this paper for the analysis of alkaloids in poisonous Datura ferox seeds of Argentina, from which previously only quantitative analysis for scopolamine was known. Five additional tropane alkaloids are now identified as 3 alpha-tigloyloxytropane (tigloyltropeine), 3-phenylacetoxy-6 beta,7 beta-epoxytropane (3-phenylacetoxyscopine), aposcopolamine (apohyoscine), 7 beta-hydroxy-6 beta-propenyloxy-3 alpha-tropoyloxytropane, traces of 7 beta-hydroxy-6 beta-isovaleroyloxy-3 alpha-tigloyloxytropane and a pyrrolidine alkaloid, hygrine. Two new structures, 3-phenylacetoxy-6 beta,7 beta-epoxytropane (3-phenylacetoxyscopine) and 7 beta-hydroxy-6 beta-propenyloxy-3 alpha-tropolyoxytropane, are proposed on the basis of their spectra. Hyoscyamine, nicotine and tropane N-oxides were not detected in all samples studied.