The antioxidation property of vitamin E-coated dialysis membrane is effective for reduction of oxidative stress. Effect of amount of vitamin E coating on antioxidation property has been poorly understood yet. In the present study, we evaluated a relationship between amount of vitamin E coating and antioxidation property using a superoxide probe of 2-methyl-6-p-methoxyphenylethynylimidazopyrazinone (MPEC) by the optical fiber method to determine optimum amount of vitamin E coating and to improve antioxidation property of the vitamin E-coated dialysis membrane. Furthermore, from the viewpoint of reuse, we examined recovery of oxidized vitamin E by vitamin C treatment. In conclusion, it is necessary to coat polysulfone dialysis membranes with vitamin E at over 74 mg/m(2). The antioxidation property is recoverable by treating dialysis membrane containing oxidized vitamin E with vitamin C. By administrating vitamin C, higher antioxidation property may be realized with a small amount of vitamin E coating. (c) 2007 Elsevier B.V. All rights reserved.