Abstract: OBJECTIVE To promote the clinical awareness of cross allergy and prevent the occurrence of medical errors. METHODS Prescribing information on cross allergy in “Contraindications” was derived from a software. Records of drug counseling, cases of medical errors and near misses in an online reporting system were analyzed. Data mining was performed. Clinical pharmacological interventions were conducted and the effects were evaluated. RESULTS Besides 27 kinds of drugs within pharmacologically similar class involving cross allergy, there were seven kinds of drugs with complete different pharmacological effects. Similarity in chemical structures was the main case of cross allergy. Excipients were related with cross allergy. Prescribing information in some drugs had unscientific descriptions on cross allergy associated contraindications, lacking clinical value in guiding safe use of medication. There were difference in descriptions on cross allergy in some drugs within pharmacologically similar clas, and some domestic and imported products. The problem of cross allergy of drugs involving different pharmacological effects was dangerous and not easy to be detected. After pharmacological interventions, awareness was greatly increased and the occurrence rate of medical errors and similar mistake decreased by 97%. CONCLISION Severe potential safety hazard might exist if more attentions are not paid to cross allergy aspect. The comprehensive pharmacological interventions are very effective. Applications of information technology and data maintenance are pivotal for continuous quality improvement in cross allergy aspect.