In the glucosamine polysaccharide of articular cartilage, the content of chondroitin sulfate is the largest, which is formed by the repeated connection of the disaccharide units composed of glucuronic acid and galactosamine sulfate.

　　Chondroitin sulfate is connected with collagen fibers to stabilize cartilage matrix. In addition to articular cartilage, chondroitin sulfate is also abundant in other tissues of the body such as tendons, bones, intervertebral discs and heart valves, besides serving as a constituent of cartilage matrix. Chondroitin sulfate can exert its therapeutic effect on osteoarthritis through the following two mechanisms.

　　1. It can competitively inhibit the activity of degrading enzymes and reduce the damage of cartilage matrix and synovial fluid components.

　　2. Reduce the formation of fibrin and thrombosis, and improve blood circulation in synovium and subchondral acupoints.