Vitamin C and the Common Cold.

Huge doses of vitamin C, from one to ten grams daily, are recommended by some scientists as a treatment for and preventative against the common cold. But the prolonged use of such large doses may be dangerous, because there is evidence that breakdown products of vitamin C formed in the body (for instance, oxalic acid) are a threat to health. Also large doses of the vitamin can enhance the dangerous effects of certain toxic substances in food. It would obviously be both easier and safer for the public to take vitamin C in the smaller quantities in which it is found in certain foodstuffs. Citrus fruits, such as oranges and lemons and also blackcurrants, are particularly rich in vitamin C, the average orange containing about 30mg.