Coeliac disease is a disorder characterised by intolerance to wheat gluten and related proteins from rye and barley, ingestion of which leads to a harmful immune activation in the small intestinal mucosa. The symptoms are often vague and do not suggest an intestinal disorder. The diagnosis is often easy once the question is raised; it requires a combination of serological tests and small intestinal biopsies. Coeliac disease can also exist with a normal serology. The trend in many countries is to require less pronounced mucosal abnormalities than previously for the diagnosis.