The gluten-free and casein-free (GFCF) diet is one of the more commonly implemented diets by parents. Gluten is a mixture of proteins found in wheat and related grains such as barley and rye as well as in many processed and prepackaged food products. Foods that contain gluten can also be used to alter the taste and texture of foods. Gluten-free diets are often combined with a casein-free diet. Casein is a protein found in dairy products.
This being said, for most children, gluten is completely harmless. Despite the wide-spread use of GFCF as an alternative diet in autistic children, research does not support it as an effective treatment of autistic related-symptoms.