Chondroitin sulfate (daily 3g. per os) was administered to fifty cases of painful disorders, such as hemicrania, neuralgia, chronic rheumatoid arthritis, perialthritis, etc. And amelioration was observed in 34 cases (68%). Chondroitin Sulfate promotes the blood clotting time by intravenous injection, but has no influence on blood viscosity. It inhibits the action of cholin esterase slightly in vitro and shows a tendency to increase peripheral circulation by Laewen-Trendelenburgs method. It showed no definite effect on blood pressure in the above-mentioned patients. By Magnus method it was shown that chondroitin sulfate accelerates the motility of the isolated rabbit intestine and suppresses the action of adrenalin. Chondroitin sulfate increases the permeability of tissue, but it shows a slight inhibitory action on testicular byaluronidase. Peroral administration of chondroitin sulfate promotes diuresis, increases the elimination of total sulfate and diminishes the neutral sulfur in the urine.