Megadose Vitamin C

James Metz, MD
Abramson Cancer Center of the University of Pennsylvania
Last Modified: November 1, 2001

Alternative and complementary medical techniques are gaining popularity in the treatment of cancer. One such treatment is the use of megadose vitamin C. Linus Pauling, Ph.D. and Ewan Cameron, M.D. wrote Cancer and Vitamin C in 1979. They claimed high doses of Vitamin C could significantly improve survival in cancer patients. It was recommended cancer patients take 10,000 mg of Vitamin C daily based on their research.

They reported a study of 100 terminal cancer patients treated with megadose vitamin C who had a significant survival advantage when compared to historical controls. Review of the study demonstrated significant bias and statistical problems. The "terminal" cancer patients who were treated with Vitamin C all came from Dr Cameron?s practice while the historical controls were "terminal" patients who came from other practices in the area. It is conceivable that significant selection bias occurred between Dr. Cameron?s patients given Vitamin C and the patients of other physicians who were not offered any additional treatments.

Because of Dr. Pauling?s reputation, the Mayo Clinic performed a prospective randomized study to evaluate Vitamin C. Patients with advanced cancer were randomized to 10 gm of Vitamin C vs. a placebo. The study was criticized by Dr. Pauling for poor design, and the study was repeated twice. Each time the study was adjusted with consideration of the criticisms of Dr. Pauling. Similar results were obtained in all three studies performed at the Mayo Clinic. There was no difference in patient comfort or survival in any of the studies.

Side effects of megadose vitamin C include diarrhea, renal stones, iron overload, and gastrointestinal discomfort. Vitamin C and Cancer remains on the shelves of bookstores throughout the country. There are ardent supporters of megadose vitamin C despite the strong scientific evidence refuting its use in the treatment of cancer.

Based on the current scientific literature, megadose vitamin C is not recommended for the prevention or treatment of cancer.

For further information on this topic, please see "High Doses of Vitamin C Are Not Effective as a Cancer Treatment," an article by Stephen Barrett, MD, of QuackWatch.com.