During 90 days of elimination diet nineteen children with food allergy manifesting atopic dermatitis were treated with either 120 mg/day of thymomodulin (10 subjects) or placebo (9 subjects) in a double blind design. After this period an improvement in skin lesions was observed in both groups. Subsequently a food challenge was performed for two weeks: in the group treated with thymomodulin skin lesions did not modify while they worsened in the placebo group and the comparison was statistically significant (p less than 0.01). Before the beginning of the trial laboratory assessments evidenced an increase in total and specific IgE serum levels, which decreased by the end of the study only in the group receiving the thymic derivative (p less than 0.05).