The present invention provides a composition for treating a joint diseasecontaining as an active ingredient thereof a monovalent metal salt of alginicacid for which the endotoxin level thereof has been lowered to an extent thatdoes not substantially induce inflammation or fever. As a result, it ispossible to provide a composition for treating a joint disease which has theeffects of protecting cartilage from mechanical irritation, inhibitingdegenerative changes in cartilage caused by wear and inflammation, repairingcartilage injuries, suppressing inflammation and pain of joint tissue,inhibiting degeneration of synovial tissue, and inhibiting osteochondraldestruction.
