We investigated the role of vitamin C or rutin on neuropathy and lung damage of diabetic mellitus(DM) rats. Norepinephrine content was significantly decreased in sciatic nerves of DM rats compared with non-DM controls but vitamin C had no effect on decreases of norepinephrine. 2,4-dinitrophenylhydrazine (DNPH) incorporation, which is biomarker of protein oxidation, was increased in sciatic nerve of DM rats as compared with normal control. However, vitamin C had no effects on increases of DNPH incorporation . We measured the content of conjugated dienes (CD) as a biomarker of lipid oxidation in sciatic nerve. CD was increased in DM as compared with normal control, Vitamin C or rutin had no effects on increases of CD. However, Rutin plus vitamin C significantly decreased the content of CD as compared with CIM rats. In lung of DM rats, DNPH incorporation or CD was increased as compared with normal control. Vitamin C or Rutin had no effects on increases of CD However, Rutin plus vitamin C significantly decreased the content of DNPH incorporation or CD in lung tissue. Vitamin C caused marked pathological changes such as the increases of parenchyma and the thickening of alveolar septa in the lung of DM. Rutin had protective effects on the pathological changes in the lung of DM rats. In conclusion, Vitamin C had no effects on oxidative parameter, such as DNPH incorporation or CD, and on the decreases of norepinephrine content in DM rats. Vitamin C caused the marked pathological changes in the lung of DM rats but rutin had protective efforts against the pathological changes.