In conclusion, drinking orange juice increased vitamin C concentrations and reduced oxidative stress in vivo by lowering the concentration of F2-isoprostanes, a finding that provides new evidence of the health benefits of eating fruit. Drinking 2 glasses of orange juice (500 mL/d) containing 250 mg vitamin C increased vitamin C concentrations in plasma and reduced the concentrations of 8-epi-PGF2 and uric acid. Total vitamin C was significantly and inversely correlated with 8-epi-PGF2. These effects were more accentuated among smokers than among nonsmokers.These findings suggest that the protective effect of vitamin C is greater in persons with higher stress and that higher concentrations of vitamin C in tissues can be gained by drinking orange juice daily. Evaluation of the health-promoting properties of vitaminC in fruit deserves further attention.