A gluten-free casein-free diet (GFCF diet), also known as a gluten-free dairy-free diet (GFDF diet), is a diet that does not include gluten (found most often in wheat, barley, and rye), and casein (found most often in milk and dairy products). Despite an absence of scientific evidence, there have been advocates for the use of this diet as a treatment for autism and related conditions.