Constituents of Ephemerantha lonchophylla (HOOK. f.) P. F. HUNT et SUMMERH, which is used as a source plant of the Chinese crude drug "Shi-Hu", were examined and four new phenolic compounds, 3-O-methylgigantol (2), ephemeranthoquinone (3), ephemeranthol-A (5), and ephemeranthol-B (7), and a new diterpene glucoside named ephemeranthoside (9) were isolated along with four known compounds, denbinobin (1), 4, 7-dihydroxy-2, 3-dimethoxyphenanthrene (4), erianthridin (6), and gigantol (8). The structures of the new compounds were determined on the basis of spectroscopic data.