Sixty-seven children under 2 years of age presenting with a classic clinical picture of coeliac disease with a severe small-intestinal mucosal lesion were investigated. All improved clinically and histologically on a gluten-free diet. During gluten challenge the mucosal damage recurred in 64 (95.5%) children, thus fulfilling the criteria for coeliac disease formulated by the European Society for Paediatric Gastroenterology and Nutrition. Three (4.5%) children had no mucosal relapse 2 years or more after return to a gluten-containing diet. These children were classified as having transient gluten intolerance. The low frequency of non-relapsers in the present study calls into question the practice of performing gluten challenge.