After the internal use of daily 3 grams of crude chondroitin sulfate cholinesterase activity of serum decreased and elimination of glycuronic acid in urine increased, but no definite change in serum mucoprotein level was observed. Mucoprotein in serum showed a positive　linear correlation to erythrocyte sedimentation rate, and　chondroitin sulfate promoted the e.s.r. in vitro and in vivo. Chondroitin sulfate showed no marked influence on phagocytosis of human leucocytes in vitro, but it promoted the production of agglutinin in rabbits by subcutaneous injection．