Anticomplementary activity of hederagenin and related saponins isolated from Dipsacus asper was investigated in vitro. HN saponin F (3) was most potent with $IC_{50}$ value of$ 3.7{ imes}10^{-5} M$ followed by 3-O-${eta}-D-glucopyranosyl-(1{ ightarrow} 3)-{alpha}-L-rhamnopyranosyl-(1{ ightarrow}2)-{eta}-L-arabinopyranosyl$ hederagenin $28-O-{eta}-D-glucopyranosyl-(1{ ightarrow}6)-beta$-D-glucopyrano side (8), $3-O-{eta}-L-arabinopyranosyl$ hederagenin </TEX>$28-O-{eta}-D-glucopyranosyl-(1{ ightarrow}6)-{eta}-D-glucopyranoside$</TEX> (5), dipsacus saponin A (4), and hederagenin (1) on the classical pathway (CP) of complement system, while the saponins 3-5 did not show the inhibition of hemolysis and rather increase the hemolysis on the alternative pathway (AP). However, all of C-3 monodesmosides [prosapogenin CP (2), dipsacus saponin B (6), and dipsacus saponin C (7)] evoked hemolysis directly on the erythrocytes.