Hypersensitivity reactions to drugs used in general anesthesia are responsible for 9–19% complications of anesthetic procedures. Identification of culprit drug is difficult because typically several drugs from different pharmacological classes are used at the short time and because of limited possibility of obtaining of anamnestic data from a patient. Hypersensitivity may be caused by different pathomechanisms. Skin tests are the main diagnostic procedure and only in exceptional cases provocations are performed. Apart from drugs other factors such as latex, volume replacement therapy and antiseptics such as chlorhexidine should be taking into consideration.