The majority of the self-reported allergies were in fact simply accepted adverse effects of the drugs concerned. The patients' reported drug 'allergy' history was generally well respected by anaesthetists and other medical staff. There were 13 incidents, mainly involving morphine, where patients were given a drug to which they had claimed a specific allergy. There were 101 incidents in 89 patients where drugs of the same pharmacological group as that of their allergic drug were used. There were no untoward reactions in 84 patients who had claimed a prior adverse reaction to penicillin who were given cephalosporins. There were no sequelae from any other events. While anaesthetists generally respected patients self-reported 'allergies', more attention needs to be paid to the accurate recording of patients' events and a clear distinction should be made both in medical records and to the patient between true drug allergy and simple adverse drug reactions.