An immunological study of 163 patients with different forms of bronchial asthma revealed a distinct disturbance of the cellular link of immunity in these patients. Vilosen (a native non-protein immunomodulator extracted from the thymus of animals) possessing a prevailing action on T-cells was used for correction of the immune disorders. It was found that vilosen proved effective in the complex treatment of patients with atopic associated forms of bronchial asthma.