Total and specific IgE have been measured in serum, suction blister fluid and jejunal aspirate in patients with various atopic disorders in an attempt to increase our knowledge of the association between food allergy and adult atopic eczema. We found (a) that patients with atopic disorders, irrespective of whether the disease affects primarily the skin or airways, have raised IgE concentrations that are largely attributable to antibodies directed against inhaled allergens; (b) that IgE antibodies against food allergens account for an appreciable amount of the total IgE in patients with atopic eczema though not as much as that contributed by inhalants; and (c) that in patients with atopic eczema, most of the IgE is produced at sites other than the intestine or skin.