Abstract
The food colouring carminic acid redox cycles to produce free radicals. These radicals, in the presence of trace amounts of iron salts, readily damage membrane lipid and degrade the carbohydrate deoxyribose. Damage to membrane lipid appears to involve mainly organic oxygen radicals such as alkoxy and peroxy radicals, whereas that to deoxyribose implicates the hydroxyl radical formed in a Fenton‐type reaction. Antioxidants and iron chelators prevent such damage.