Anaphylaxis is an often severe, potentially life-threatening symptom complex. Urticaria, airway edema, vascular collapse, asthma, abdominal pain, and diarrhea are common clinical signs. Recently recognized syndromes of anaphylaxis include reactions due to exercise, food preservatives, aspirin, steroids, dialysis, various serums, and human seminal fluid. Initial therapy is directed at maintaining an effective airway and circulatory system. Administration of aqueous epinephrine is always indicated. Other measures may include oxygen delivery by controlled flow, administration of an aerosolized beta agonist, slow infusion of aminophylline, and rapid infusion of intravenous fluid. Patients with severe acute reactions should be monitored in-hospital.