The hypothesis that oxidative damage due to free radicals is an important cause of aging is the subject of much research and even more interest among the public and lay media. An increasing number of older people are asking whether they should be taking antioxidant vitamins, despite their considerable cost. Epidemiological and laboratory evidence indicates that oxidative damage caused by oxygen free radicals is important in many of the major diseases of older age. It is also clear that a diet high in antioxidants protects against these diseases, including many cancers and ischaemic heart disease. However, it has not been proven whether antioxidant vitamins, taken as dietary supplements, provide the same level of protection as a diet that is rich in fruit and vegetables. Although there appears to be no reason to discourage older people from taking vitamin E (tocopherols) and ascorbic acid (vitamin C), the best advice to give them is to reduce their intake of xenobiotics, to drink tea instead of coffee, and to eat liberal amounts of fruit, vegetables, nuts, soya beans and lentils. The use of beta-carotene as a dietary supplement should be discouraged.