Objective-To investigate the nature and accuracy of information carrie
d by patients about their drug allergies. Subjects-2500 new adult pati
ents. Setting-Accident and emergency department of a tertiary referral
centre. Methods-Patients were questioned about drug allergies. Where
they claimed allergies, general practitioners were contacted for corro
boration. Results-242 patients (9.7%) claimed 276 allergies; 32 differ
ent drugs were implicated. Penicillin was implicated most often (151 p
atients); 38 patients could not remember what they were allergic to; 2
1 described severe reactions, but four could not remember the drugs in
volved. Only seven patients carried evidence of their allergies. Gener
al practitioners were contacted about 240 of the drug allergies; only
114 were confirmed as described. Conclusions-Many patients who believe
themselves to have drug allergies are poorly informed about them. Eme
rgency prescribing for these patients may risk anaphylaxis. The future
acceptance of ((Smart cards'' would reduce this risk. In the meantime
, patients with drug allergies should be strongly encouraged to carry
evidence of their allergies.