Strict criteria for the diagnosis of temporary gluten intolerance are formulated in the light of the case of an 8-week-old infant with severe diarrhoea and failure to thrive, who recovered on an elimination diet that was gluten-free. 8 weeks later an oral challenge with 2.5 g twice daily of powdered gluten for one day produced diarrhoea, weight loss, and impaired xylose absorption. Gluten was successfully reintroduced into the diet 9 months later without incident. Jejunal histology remains normal after 26 months of a daily diet that contains 5 to 10 g gluten.