We report the results of a morphometric study of jejunal biopsy specimens from 18 children with eczema due to food allergy. The measurements were compared with those for 13 age-matched children without gastrointestinal or immunological diseases. The patients' ages ranged from 2 months to 4 years. In 14 the food responsible for the symptoms was cow's milk. During the challenge tests with suspected foods 10 children had skin symptoms only (group I) and eight had gastrointestinal symptoms in addition (group II). Both groups showed a significant decrease in the villus/crypt ratio, mostly due to an increase in crypt depth. The counts of lymphocytes and plasma cells in the lamina propria and of intraepithelial lymphocytes did not differ from those seen in the controls. Four patients had increased counts of jejunal eosinophils, but the mean count for the whole group was not significantly increased. Considered nine measurements only five of the patients had moderate changes in jejunal morphology.