In 1973 Dr Ben Feingold, a California alergist, proposed that salicylates, artificial flavors, and artificial food colors are a cause of hyperactivity. Dr Feingold recommended a diet free of these substances as both treatment and prevention of the condition. He has published two popular books on the subject, Why Your Child Is Hyperactive (1974) and The Feingold Cookbook for Hyperactive Children (1979). Many parents have adopted the diet for their hyperactive children, and some have reported a noticeable improvement in their child's behavior when the diet was followed. In recent years a number of experiments have been carried out to evaluate the relationship between hyperactivity, salicylates, artificial flavors. The data indicate that the symptoms of the vast majority of cases of children labeled "hyperactive" are not related to additives in their diet.