Health claims for foods are permitted in an increasing number of countries but there are very few studies evaluating the effect of such claims on purchase behavior and consumer health. There are significant differences between countries, but in general consumers see health claims as useful, they prefer short succinct wording rather than long and complex claims, and they believe claims should be approved by government. Consumers view a food as healthier if it carries a health claim and this “halo” effect may discourage them seeking further nutrition information. Consumers do not clearly distinguish between nutrient content, structure-function and health claims. There is some evidence that use of health claims improves the quality of dietary choices and knowledge of diet-disease relationships.