Effect of Mylabris sidae(MS) and Epicauta gorhami(EG) polysaccharide fractions on the inflammation and immune responses were studied in vivo. MS and EG contained cantharidin about 0.61 and 0.65%, respectively. It was shown that MS and EG polysaccharide fractions at a oral dose of 100 mg/kg have the significant anti-inflammatory and analgesic activity; They inhibited significantly the carrageenin-induced inflammation and acetic acid-induced writhing syndrome. They accelerated significantly the carbon clearance and the phagocytosis of colloidal carbons by Kupffer cells in liver, but they at a oral dose of 100 mg/kg suppressed significantly the Arthus reaction in the sheep red blood cell(S-RBC)-sensitized mice in accordance with the inhibition of haemaglutinin titer, haemolysin titer and plaque-forming cells. On the other hand, they at a oral dose of 200 mg/kg accelerated slightly the oxazolone-induced dermatitis in rats and delayed hypersensitivity in the S-RBC-challenzed mice in consistent with the increase of rosette forming cells. As the above results, it exhibited that MS and EG polysaccharide fractions inhibited the humoral immune responses, but they accelerated the function of macrophages and cellular immune responses. EG polysaccharide fraction had more active than MS polysaccharide fraction.