The first thing to think about is what is gluten and why is it dangerous for someone that has Coeliac / Celiac Disease, or with Gluten Intolerance. Gluten is a protein found in Wheat, Rye or Barley when these grains have been consumed a person who is unable to digest the protein becomes ill, as the intestine thinks that the protein is an invader. There are lots of other grains that contain gluten and are also unsafe. Some products have hidden ie. Malt Barley, Soy Sauce.