Fifteen children with an initial diagnosis of coeliac disease underwent gluten challenge either because they had never had a jejunal biopsy or because they had had one during the first 2 years of life. The challenge was preceded by a biopsy; clinical symptoms, the cellobiose/mannitol permeability test, and gliadin and endomysial antibody measurement were used to determine the timing of the confirmatory biopsy: it was performed if one test result was repeatedly abnormal or two results were concomitantly abnormal. Gliadin antibodies increased early (already 7 days after the reintroduction of gluten to the diet), but in many cases they returned to normal values thereafter. Increased intestinal permeability to sugars and even more positivity of endomysial antibody were good predictors of histologic relapse. The sequential use of laboratory tests during gluten challenge may significantly shorten its duration.