The prevalence of allergic reactions in general opulation shows a constant rise. It has been estimated that up to 40% of surgical patients have a positive history of some kind of allergy. These patients represent a challenge during perioperative evaluation, since they can be exposed to a large variety of drugs and substances during surgery and anesthesia. A lot of adverse drug reactions show similar clinical presentation with allergic reactions. The latter are usually poorly explored since preoperative allergology testing is performed in a limited number of patients. Management of patients with history of allergy is impeded by the fact that most of allergens cross-react in a manner that is not always easy to predict. Allergies can manifest themselves with a broad spectrum of clinical symptoms, ranging from mild skin symptoms such as itch and urticaria, to a life-threatening anaphylactic reactions followed by hypotension, bronchospasm and cardiovascular collapse. Prevention of allergic reactions during perioperative period requires detailed history taking in order to identify patients at risk, optimization of anesthesia strategy, pharmacological premedication and further allergology diagnostic work-up in selected cases.