Serum and rectal total and specific IgE were measured in eleven children with atopic dermatitis and eight with atopic dermatitis and associated wheezing. Specific IgE to food and inhalant allergens in rectal washings were found in fourteen patients. Of the seventy-six allergens which gave positive results, twenty were positive in both serum and intestine, thirty in serum alone and twenty-six in intestines alone. Specific intestinal IgE were confirmed by food challenge in three out of four patients whose skin-prick test and serum RAST were both negative. Local production of these antibodies was demonstrated by the ‘double ratio’ of Dcuschl and Johansson [1], and the ‘specific activity ratio’ of Platts-Mills [2]. Positive ratios (> 1) were obtained with both formulas for twelve of fourteen allergens tested. These data suggest that gut-associated lymphoid tissue may play a role in the pathogenesis of atopic disease.