Severe allergic protein-losing enteropathy has been described in childhood atopic dermatitis (AD). Minor morphologic and functional abnormalities of the gastrointestinal mucosa, including altered permeability to oligosaccharides, are not uncommon in this condition, but the prevalence of occult enteric protein loss is unknown. We measured the random fecal alpha 1-antitrypsin (AAT) concentration, an indicator of enteric protein loss, in children with and without AD and found no significant difference between the groups. In half of the patients with AD, gastrointestinal permeability to oligosaccharides was also measured, and no relationship between this and fecal AAT was found.