Alternative cancer treatment: Can vitamin C kill cancer cells?

I have been reading about vitamin C as an alternative cancer treatment. What can you tell me about it?

- Cindy / Oklahoma

Mayo Clinic oncologist Timothy Moynihan, M.D., and colleagues answer select questions from readers.

Answer

The use of vitamin C in alternative cancer treatment isn't new. Proponents claim that large doses of vitamin C are toxic to cancer cells. However, there is no reliable evidence to support this theory.

Studies in the 1970s first suggested that large doses of supplemental vitamin C might be of some benefit in the treatment of cancer. But these studies were later found to have serious flaws. Subsequent well-designed, randomized, controlled trials of vitamin C and cancer found no such treatment benefit.

More recently, intravenous (IV) vitamin C has been touted to have different effects than does Vitamin C taken orally. This has sparked renewed interest in the use of IV vitamin C as a cancer therapy. However, until clinical trials are completed, it is premature to determine what role, if any, IV vitamin C may play in the treatment of cancer.