The development of toxic fibrosing alveolitis (ICD-10 code: J70.1-J70.8) is caused by the toxic effect of chemicals on the respiratory section of the lungs, as well as the damaging effect of immune complexes. In children, toxic fibrosing alveolitis is most often associated with the use of various drugs (sulfonamides, methotrexate, mercaptopurine, azathioprine, cyclophosphamide (cyclophosphamide), nitrofurantoin (furadonin), furazolidone, hexamethonium benzosulfonate (benzohexonium), propranolol (anaprilin), hydralazine (apressin), chlorpropamide, benzylpenicillin, penicillamine).