Until quite recently most physicians adhered to the belief that the only function of vitamins was to prevent deficiency diseases such as scurvy and pellagra. When Linus Pauling founded orthomolecular medicine twenty-five years ago by suggesting that vitamins might have other functions than this, he was greeted with scorn, derision and outright hostility by the orthodoxy. Today the situation is entirely transformed- There is now an enormous literature on the role of vitamins in the body other than their prevention of deficiency diseases. This is based largely on the discovery of the wide role that oxidative stress plays in many diseases and of the role of antioxidant vitamins in preventing and combating these diseases. The only point of disagreement in main stream medicine today is whether the right amount of protective antioxidant vitamins can be obtained by improving one's diet alone - i.e. by eating more fruits and vegetables - or whether supplements are needed.