Our clinical and experimental studies have so far demonstrated, that the drugs used in anaesthesia; such as hypnotics, sedatives, narcotics or muscle relaxants, release histamine. The intravenous short acting anaesthetic etomidate has not shown either in experimental studies or in clinical use for 10 years any anaphylactoid reaction. The benzodiazepines are another group of drugs which appear not to release high amounts of histamine. Accurate studies on volunteers as well as on patients on the application of H1- and H2-receptor antagonists have demonstrated an effective inhibition of the anaphylactoid reaction. We suggest that in case of a history of allergy H1- and H2-receptor antagonists should be administered as a prophylactic premedication.