In the 24 h after ingestion of 100 microCi of 51Cr-labelled EDTA (edetic acid), controls (22) excreted less than 2.5% of the dose, whereas patients with coeliac disease in relapse (6) excreted between 4.7% and 14.7%. In 10 patients with coeliac disease in complete clinical and histological remission, excretion of 51Cr-labelled EDTA was between 3.0% and 12.7% of the dose. This indicates a persistent or primary defect of intestinal permeability in these patients and confirms previous in vitro results. The reproducibility, safety, simplicity, and accuracy of the procedure suggest that it may be suitable as a routine screening test for coeliac disease.