The saponins of two- and four-year-old American ginseng plants (Panax quinquefolium L.) (Araliaceae) collected in July and September were studied. American ginseng saponins (panaquilins) differ from Korean ginseng $(Panax ginseng;C.A.;M_{EYER})$ saponins (ginsenosides). The American ginseng saponins separated and named were panaquilins A, B, C, D, E-1, E-2, E-3, G-1, G-2, (c) and (d). One-dimensional thin-layer chromatography did not completely separate panaquilin mixture and was subject to misinterpretation. The panaquilins were more accurately separated and identified by the two-dimensional thin-layer method established. Some differences in American ginseng saponins were dependent upon the plant age, time of collection, and part extracted. The American ginseng sapogenin components are panaxadiol (panaquilins B and C), oleanolic acid (panaquilin D) and panaxatriol (panaquilin G-1). The panaquilins E-1, E-2 and E-3 mixture contained both panaxadiol and panaxatriol. The genins of panaquilins A, (c), (d) and G-2 were not identified. In addition, ${eta}-sitosterol$ and stigmasterol were identified from the root ether extracts.