The distribution of phenolic components of Korean ginseng (Panax ginseng KG) and American ginseng (Panax quinquefolium, AG) were compared by thin-layer chromatography (TLC). Silica gel TLC gave 3~4 spots, while $NH_2$ HPTLC 5~6 spots, which were colored by both $FeCl_3$/$K_3Fe(CN)_6$ and Folin-Ciocalteu. The distribution of phenolic components was quite different between KG and AG. Especially, a polyphenol (m.w. 578), which had been isolated from KG by the author, was not found in AG. This result suggests that the polyphenol could be used as an index compound for the differentiation of KG from AG.