A large experience in specific immunotherapy is reviewed in order to assess the safety of this treatment. From 1968 through September 30, 1993, 300,086 injections were administered to 6,319 patients suffering from allergic asthma and/or rhinitis. Systemic reactions reported during the whole period were 184 (0.061%) in 134 subjects (2.1%) and consisted of: urticaria (59.3%), mild asthmatic attacks (23.9%), asthma and urticaria (9.7%), and spasmodic rhinitis (7.1%). The absence of cases of anaphylaxis confirms the safety of specific immunotherapy. This kind of treatment should be considered as first-line therapy, if carried out in a specialized setting.