Five saponins (I-V) have been isolated from the flowers of Lonicera fulvotomentosa Hsu et S.C. Cheng (Caprifoliaceae). This paper reports the structural determination of V, a new triterpenoid saponin named fulvotomentoside A, and characterization of I and II. Fulvotomentoside A, C58H94O26, was obtained as white crystalline needles, mp 215-7 degrees C, [a]D27.5-14.9 degrees (c 0.98, MeOH). Its structure was elucidated to be 3-O-beta-D-xylopyranosyl-(1-3)-alpha-L-rhamnopyranosyl-(1-2)- alpha-L-arabanopyranosyl-hederagenin-28-O-beta-glu cop yranosyl-(1-4)-beta-D- glucopyranoside mainly by spectroscopic analysis (IR, MS, 1H and 13CNMR) and chemical degradation. C41H66O12, mp 259-262 degrees C, and II, C46H74O16, mp 222-7 degrees C, were identified to be alpha-hederin and sapindoside B, respectively. Several constituents of L. fulvotomentosa and L. macranthoide are effective in decreasing CC1(4) and D-Galactosamine-induced liver injuries, and this effect appears to be due to the decrease of lipid peroxidation of CC1(4).