Anaphylaxis due to allergic or non-allergic hypersensitivity to drugs is an acute fatal or potentially fatal reaction. The estimate rate of 3.2 cases of drug-associated fatal anaphylaxis per 100.000 inhabitants per year seems to be approximately 10 times greater in hospitalised patients. The most common agents that are responsible for anaphylaxis in hospitalised patients are muscle relaxants, latex, antibiotics, anaesthesia-inducing drugs, plasma expanders followed by local anaesthetics and iodinated radio contrast media, and many others. Antibiotics and non-steroid anti-inflammatory drugs (NSAID) are the common cause of anaphylaxis in non-hospitalised patients. Predictive tests for high-risk patients have not been established. However, several procedures for prevention are proposed. These include preoperative screening to detect sensitisation to anaesthetic drugs and latex, or pre-treatment with antihistamines and corticosteroids to prevent anaphylaxis to iodinated contrast media. Challenge tests are useful for the determination of a safe anaesthetic or NSAID. Unfortunately, the causative agents cannot be identified in all cases of anaphylaxis. Subjects at risk for idiopathic anaphylaxis should have epinephrine available for self-administration.