In summary, immunotherapy is probably a useful treatment for selected cases of allergic airway disease. Patients should be selected who are allergic and who have at least moderately severe illnesses. Using commercially available solutions of antigen extracts, a therapeutic response may be expected in about three quarters of patients in that they will be able to reduce or eliminate medications. The disadvantages of treatment include its inconvenience and cost, its frequent ineffectiveness, and its risks of anaphylaxis; many of these disadvantages are eliminated by newer antigen preparations.