[Vitamin C. Its clinical use and state of the art]

This is a review of the most relevant articles on the vitamin C-based therapy with emphasis to high per os and parenteral doses that might be effective on calories utilization, energy production, mythocondrial red-ox function, gene expression and metabolism. Ascorbic acid treatment in tumor bearing patients is a puzzling issue whose rationale is based on low vitamin plasma concentration and cancer uptake and sequestration; furthermore high parenteral dosages should be required to achieve a putative oxidative damage on tumor DNA, by this antioxidant molecule; thus bioavailability and metabolism as well as clinical effectiveness are reviewed on the basis of the evidence based medicine: specific evidence of vitamin C efficacy is quite limited, but areas like diabetic vascular complications and sideropenia might benefit of the treatment; high parenteral doses might be useful, perspectively also in relapsing urinary tract infection, after conventional treatment failure, due to the high output of ascorbic acid and potential saturation of the target tissues.