Both the Celiac Disease Foundation and the Mayo Clinic offer comprehensive lists of foods that contain gluten, as well as suggestions for foods that do not. The CDF groups foods by ingredients that contain gluten, as well as by types of foods that are likely to have gluten in them.
When purchasing gluten-free foods, always check the ingredient list for binding agents or food additives that contain gluten. Even foods that appear to be gluten-free, such as corn tortillas, may contain wheat flour as an additive. Foods labeled gluten free are required by the Food and Drug Administration to contain less than 20 parts per million of gluten.