Fast Five Quiz: Vitamin C

Romesh Khardori, MD, PhD


June 24, 2021

Although the acute toxic dose for vitamin C has not been determined, the chronic toxic dose is more than 2 g/day. The effects of vitamin C toxicity can include the following:

  • Renal colic (ie, nephrolithiasis)

  • Diarrhea

  • Nausea

  • Rebound scurvy (in infants born to women taking high doses)

  • Hemolysis (if glucose-6-phosphate dehydrogenase deficiency is present)

  • Dental decalcification

  • Increased estrogen levels

  • Occult rectal bleeding

Although high vitamin C intake does not appear to cause excess iron absorption in healthy individuals, chronic consumption of high doses of vitamin C may result in tissue damage due to iron overload in those with hereditary hemochromatosis.

Patients with suspected vitamin C toxicity should undergo urinalysis, renal function testing, and serum iron level assessment. If potentially lethal co-ingestions are present, perform gastric lavage if the patient presents within 1 hour postingestion. Always check whether the vitamin overdose included iron supplements and manage such an overdose aggressively.

Read more about the workup of vitamin toxicity.


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