There is a well-rehearsed chant in the integrative management for ASD individuals, “Gluten free- casein free diets are step 1”. This is based on the dietary exorphin theory which suggests these foods generate bioactive peptides that act unfavourably in the brain. Where did this theory emerge from and how strong or weak is the evidence upon which this therapeutic intervention stands? Even more interesting, is there support of this theory in a wider range of mental health presentations such as schizophrenia, post-partum psychosis and depression. Is there such a thing as milk madness for a subset of these patients?