Treatment of allergic disorders by hyposensitizing antigenic injections has found widespread acceptance as a relatively simple, safe, and effective procedure. However, the mechanisms by which such treatment may be beneficial are still under study and, to date, essentially unestablished. The safety of this type of treatment has recently been challenged by the identification of several disease entities which clinically resemble atopic asthma, but are in reality caused by other immunologic mechanisms not amenable to hyposensitization therapy, and by some reports of cases of lymphoproliferative disease with apparent association with allergy injections. It is important to establish clear-cut criteria for (1) the presence of an atopic disorder, (2) a demonstrable allergen, (3) absent alternative pathogenetic mechanisms, (4) identification of contributory psychological factors, and (5) a monitoring system regarding the safety and effectiveness in the case of each patient who is scheduled to receive prolonged injection therapy.