Coeliac disease is a permanent food intolerance with a genetic basis which persists throughout the whole life. Ingestion of gluten proteins (wheat, rye, barley, oats) causes atrophy of the jejunal villi and, as a consequence, malabsorption. Diagnosis can only be proved by three consecutive intestinal biopsies; initially on normal diet, after 12--18 months of gluten-free diet, and after a final challenge with gluten-containing food. Biochemical changes have been discussed for a long time to be of primary importance in the pathogenesis of coeliac disease. Recently, however, evidence is increasing that immunological mechanisms are primary factors in the development of the disease. A synopsis of biochemical and immunological phenomena and of membrane receptor alterations of enterocytes and immunocytes which are genetically based is more likely to answer the question of pathogenesis than any single theory. Therapeutically, life-long gluten-free diet is necessary. In some cases, after a long course the prognosis is limited by the increased incidence of malignancy.