Some recent advances in the understanding of the chemistry of gluten proteins and its relationship to the toxicity of different fractions in coeliac disease (gluten intolerance) is reviewed. Most recent studies on gluten toxicity have used in vitro analyses of cellular immune activation by gluten fractions and peptides. Our work indicates that gliadin is the most active of the different protein families found within the wheat grain and that a specific peptide sequence located in the amino terminus domain of alpha-gliadin and containing the sequence proline-serine-glutamine-glutamine was most active. Improvement in the dietary management of coeliac disease is possible by use of test kits for the detection of gluten in foods. Both laboratory kits and home test kits (suitable for use by individual coeliacs) are available and reliably detect gluten from wheat, rye and barley even after cooking or baking.