Alternative and complementary therapies may be referred to as "unproven", "nontoxic", "unorthodox", or "unconventional" therapies, and represent methods which do not have a scientifically-proven basis. The following information is intended to help people with cancer and their families make decisions about the use of such treatments. The Anti-Cancer Foundation does not, however, endorse alternative cancer therapies.

We recommend you read this information sheet together with "Making An Informed Choice". 

Rationale/ Background/ Claims

· Vitamin C is the general name for a group of compounds, chiefly ascorbic acid and dehydroascorbic acid (which is readily converted back into vitamin C in the body).

· In the 1970's Dr Ewan Cameron and Dr Linus Pauling published Cancer and Vitamin C, which proposed that taking regular high doses of vitamin C can play a part in both prevention and in the treatment of established cancer.

· Cancer patients are reportedly significantly depleted of ascorbic acid. Cameron and Pauling believe this indicates substantially increased requirements and utilisation of this substance in order to boost the person's resistance to disease.

What does the therapy involve?

· In 1991 Dr Cameron published a protocol for the use of vitamin C in the treatment of cancer. The protocol recommends that all cancer patients receiving vitamin C be given an initial 10 day course of intravenous ascorbate, followed by an oral maintenance dose to be continued thereafter. The importance of continuous rather than intermittent administration is emphasised.

. Oral vitamin C is to be taken to what is called bowel tolerance. When the body's maximum saturation tolerance is reached, diarrhoea results. The aim is to reach an oral dose which is just below this point.

. This is achieved by taking several divided doses of vitamin C throughout the day, usually in a powdered form mixed in a glass of water. The standard recommended dosage is 10 grams per day.

. In addition to vitamin C therapy, it is recommended other supplements be taken. A flyer distributed in 1991 by the Linus Pauling Institute recommended daily doses of 6,000 to 18,OOOmg (6 to 18g) of vitamin C; 400 to 1600lU of vitamin E; and 25,000 IU of vitamin A, in addition to other supplements.

Toxicity / Risks
. As the dosage levels of vitamin C are increased, absorption falls markedly. At the level of dietary intakes (about 30-180mg), vitamin C is approximately 90% absorbed. Absorption falls to 50% with a dose of 1,500mg (1.5g), and to 16% with a dose of 12,000mg (12g).

. Several reviews have concluded that vitamin C has little toxicity. Protection from toxicity is due to two factors: the efficient excretion of excess ascorbic acid in the urine when doses exceed 130mg per day; and the limited absorption capacity of the gut. With large doses of vitamin C, most passes on to the colon (large intestine). Little is known about compounds produced from vitamin C by the bacteria in the colon.

. Intestinal symptoms can occur with high doses of vitamin C, including nausea, vomiting, bloating and gas. Depletion of certain minerals (such as calcium) can occur. More serious risks include haemorrhage and rebound scurvy (ie vitamin C deficiency, occurring upon sudden withdrawal of large doses of vitamin C upon which the body has become accustomed to receiving).

· Intravenous vitamin C can harden the vein, making other intravenous therapy difficult to administer.

· High intakes of ascorbic acid increases the excretion of oxalate in the urine, which may contribute to a greater risk of kidney stone formation. High intakes of vitamin C are not recommended for people with iron storage disease (iron toxicity can occur) or in patients with chronic renal failure.

· Megadoses of the other mentioned vitamins can be dangerous, especially in the case of vitamin A, as liver toxicity and other associated effects may occur.

· It has been suggested that antioxidants (such as vitamin C) interfere with the ability of radiation and chemotherapy to kill cancer cells, due to the mechanism of action by which these treatments work. Thus combining vitamin C with these treatments should be fully discussed with a doctor.


· The evidence cited by Pauling and Cameron to support their claims has not proved to be scientifically valid. The subjects used to compare vitamin C against placebo ("dummy" pills/treatment) were not comparable, hence accurate conclusions cannot be made.

· Three studies were reported in 1979, 1983, and 1985, which were conducted in a reputable clinic according to accepted scientific protocols. It was found that patients given 10,000mg (log) of vitamin C daily did no better than those given a placebo.

Costs and Commitment

· Vitamin C is readily available at Health Food outlets.

In Summary . . .

· Many studies have demonstrated a strong link between high consumption of fruit and vegetables with a low incidence of certain cancers. Conversely, low fruit and vegetable intakes are associated with an increased risk of developing cancer.

· The relationship between overall diet and cancer tends to be strong. However, as you restrict the emphasis to individual nutrients found in foods, the relationship becomes less clear. This is probably because we have not discovered all of the important nutrients contained in foods, some of which may have cancer-fighting properties.

· It is therefore unjustified to single out a particular nutrient as protective against cancer, or indeed as a cure for cancer, until reputable scientific studies have demonstrated this to be the case.

For further information contact the:

Anti-Cancer Foundation of South Australia
(ABN 29 053 873 822)
202 Greenhill Road, Eastwood SA 5063
PO Box 929, Unley SA 5061
Tel: (08) 8291 4111
1800 188 070 country callers
Fax: (08) 8291 4122

This resource was produced in 1998 by Sally Zeunert.