Ascorbate (vitamin C, ascorbic acid) is an essential nutrient and commonly regarded as an antioxidant.It has a controversial history in cancer treatment.However, high dose of intravenous ascorbate are widely used to treat cancer and infection by complementary and alternative medical practitioners.The efficacy and underlying scientific basis are poorly understood.On the other hand, little side effects were found in these treatments and in a Phase Ⅰ clinical trial in cancer patients.Early observational studies and recent case reports show positive effect of ascorbate in cancer treatment.Furthermore, were still in lack of treatment options for a large number of cancers.Ascorbate as a low toxic and potentially effective agent may have great merits that worth investigation.