Gluten is found in wheat, rye, and barley. Oats are a separate issue. While oats do not actually contain gluten, almost all oats are grown in close proximity to wheat, rye, and/or barley. And they are processed in facilities that also process wheat, rye, and/or barley. So they are usually contaminated. But, it is now possible to buy gluten-free oats. These oats are grown and processed completely separate from wheat, rye, and/or barley. And they have been tested to make sure they meet the gluten-free standards of under 20ppm. There is a small percentage of people with Celiac Disease who have an adverse reaction to the protein in oats. So, it is best to consult with your doctor if you are going to add gluten-free oats to your diet. Your doctor will probably want to test you to make sure you are tolerating them. Please refer to Gluten-Free Diet to see all of the places that gluten can hide (i.e. thickeners, etc.).