OBJECTIVE： To investigate sulfonamide allergy item annotation in drug instructions of sulfonylureas， and to provide reference for the promoting rational clinical use of the drugs. METHODS： In Oct. 2018， the drug instructions of commonly-used sulfonylureas at home and abroad were collected by MCDEX software （online version）， Drugs@FDA of the US Food and Drug Administration website， DailyMed website， European Medicines Agency website and UK electronic Medicines Compendium website. The annotation of sulfonamide allergy was analyzed statistically in respects of non-labeled sulfonamide allergy， only labeled sulfonamide allergy contraindication， only labeled sulfonylureas allergy contraindication， labeled sulfonamide and sulfonylureas allergy contraindication. The proportion of sulfonamide allergy contraindication labelling was calculated. RESULTS： Among 174 pieces of domestic drug instructions， 67 pieces of drug instructions were gliclazide， 48 were glipizide， 23 were glibenclamide， 23 were glimepiride and 13 were gliquidone. Different pharmaceutical manufacturers reached a consensus on the sulfonamide allergy of gliquidone and glibenclamide. The proportions of sulfonamide allergy contraindication labelling were 100％ and 95.65％， respectively. However， there were great differences on the sulfonamide allergy of glipizide， glimepiride and gliclazide， and the proportions of sulfonamide allergy contraindication labelling were 70.83％， 65.22％ and 49.25％， respectively. Among 13 foreign drug instructions， 4 pieces of drug instructions were glibenclamide， 3 were glipizide， 3 were glimepiride， and 3 were gliclazide， among which 7 drug instructions were sulfonamide allergy contraindication. However， there were great differences in the sulfonamide allergy annotation of drug instructions between US and Europe. CONCLUSIONS： There are great differences in the annotation for sulfonamide allergy in drug instructions of sulfonylureas at home and abroad， which indicates that there are different opinions on the clinical significance of sulfa cross-reaction in patients with sulfonamide allergy， and sulfonamide cross-allergy is a controversial issue. It is necessary to promote the research of sulfonamide cross-allergy from the perspectives of scientific researchers， medical associations， pharmaceutical manufacturers， medical staff and patients，  and to clarify its mechanism and clinical significances.