The gluten content and nutritional adequacy of the diet of a group of adult coeliac patients supposedly following a gluten-free diet for at least one year were assessed. Results were considered in relation to the nutritional state of these patients, determined by anthropometric measurement, and the histological appearance of jejunal biopsies taken at the time of nutritional assessment. Imperfect gluten avoidance, mild malnutrition and mild histological abnormalities on jejunal biopsy were frequent findings. A careful dietary and nutritional assessment when considered in light of histological findings at jejunal biopsy helps to identify the causes of persisting symptoms or malnutrition in treated coeliac patients. A normal jejunal biopsy in a malnourished patient whose dietary compliance is good should prompt a search for an alternative diagnosis.