Chemical investigation of the inhibitory compound on leucocyte migration from Melilotus officinalis has led to the isolation and characterization of azukisaponin V $(3-O-[{alpha}-L-rhamonopyranosyl(1{ ightarrow}2)-{eta}-D-glucopyransosyl(1{ ightarrow}2)-{eta}-D-glucuronopyranosyl]-soyasapogenol B)$ as the carboxylate form, which exhibits potent leucocyte migration inhibitory activity at a dose of 6mg/rat.