Adult coeliac disease has a broad clinical spectrum and remains undetected for years. Among subclinical deficiency states, attributable to coeliac enteropathy, combined iron and folic acid malabsorption is predominant. An unexplained recurrent iron anaemia is an indication for small intestinal biopsy. Gastro-intestinal disorders are present in only 50% of the cases. Coeliac disease is frequently associated with other major histocompatibility complex (MMC)-linked diseases which are mediated by immunological mechanisms: dermatitis herpetiformis, oral ulcerations, IgA nephropathy, rheumatoid arthritis, sarcoidosis. Dermatitis herpetiformis is a useful model for examination of the spectrum of mucosal changes that typify gluten sensitivity and subliminal lesions without villous atrophy. An increased interest is devoted to the intra-epithelial T-lymphocyte population, not only in the small intestine, but at the level of the stomach and the colon. A "rectal challenge" test has been proposed for detecting gluten sensitivity in coeliac patients. Such a test could be an original method of screening, reducing so the need of small intestinal biopsy. The preliminary results are to be confirmed. Until now, jejunoscopy remains mandatory for the diagnosis and the survey of intestinal lesions related to coeliac disease.