The anti-inflammatory activities of hederagenin and crude saponin isolated from Sapindus mukorossi GAERTN were investigated utilizing carrageenin-induced edema, granuloma pouch and adjuvant arthritis in rats. The effects of these agents on vascular permeability and acetic acid-induced writhing in mice were also examined. In some experiments, the results were compared with those obtained with saikogenin A, crude platycodin, platycodigenin and oleanolic acid. Anti-inflammatory activity on carrageenin edema was observed with i. p. and p. o. administered crude saponin, while hederagenin and the other agents used showed activity only when administered i. p. Hederagenin, 100 and 200 mg/kg p. o. per day for 7 days, showed no significant inhibitory effect on granuloma and exudate formations in rats, while crude saponin, 100 and 200 mg/kg p. o., showed significant effects. Crude saponin, 200 mg/kg p. o. per day for 21 days, significantly inhibited the development of hind paw edema associated with adjuvant arthritis in rats, but hederagenin, 50-200 mg/kg p. o., did not. Crude saponin, 400 mg/kg p. o., inhibited the increase in vascular permeability and the number of writhings induced by acetic acid in mice. The results suggest that hederagenin and crude saponin, as well as the other agents used, show some degree of anti-inflammatory activity, especially in the case of saponin.