<<Disclaimer: Verify this information before applying it to your situation.>> Here's the definition of Celiac Disease as provided by the Celiac Disease foundation: "Celiac Disease is a digestive disease in which damage to the surface of the small intestine is caused by the ingestion of food products that contain gluten or similar proteins that are present in wheat, rye, oats and barley. Such proteins can also be present in hybrid grains such as triticale."