Purpose of review 

Although vitamin C is essentially a nontoxic vitamin; however, it is important to be aware regarding the safety of high doses before the wide clinical use.

Recent findings 

Minor side effects of vitamin C have been reported, many being reported in earlier studies. High doses of vitamin C (up to 1.5 g/kg three times a week as intravenously) were safe in cancer patients with normal renal function and perfect glucose-6-phosphate dehydrogenase activity. As the dose and duration of administration of vitamin C in sepsis are lower and shorter than those used in cancer patients, it seems that it is relatively safe for this population. In ongoing trials, safety of high doses of vitamin C is considered.

Summary 

Data regarding the safety of high doses of vitamin C are scant. Until more data become available, caution should be applied in the use of high doses of vitamin C in patients with hemochromatosis, glucose-6-phosphate dehydrogenase deficiency, renal dysfunction, kidney stone, oxaluria, and pediatrics.