This book presents current research on reactive oxygen species in joint physiology, including possible mechanism of maintaining hypoxia to protect chondrocytes from oxygen excess via synovial fluid hyaluronan peroxidation; radical degradation of high-molar-mass hyaluronan induced by ascorbate plus cupric ions testing of arbutin in the function of antioxidant and free-radicals degradation of high-molar-mass hyaluronan induced by ascorbate plus cupric ions. This book also explores anti-oxidative properties of the piestany-spa curative waters from healing peloid and maturation pool; potentiometric study on the interactions between divalent cations and sodium carboxylates in aqueous solution and diffusion of electrolytes and non-electrolytes in aqueous solutions.