fa پژوهشي اصیل Original Research <p>Background and Objective: Type I drug hypersensitivity reactions causes immune responses that could endanger<br> life. Therefore this study was designed with the aim of evaluation and register reactions that caused by<br> chemotherapy in hospitalized children in Rasoul Akram Hospital in 2015.<br> Methods: This is a descriptive, cross sectional study. All statistical calculation was performed using the version<br> 21 SPSS software. Significant level of tests was considered 0.05 (p <0.05).<br> Results: the incidence of hypersensitivity reactions in the study population is estimated to be 4.9%. The results&nbsp;also showed that men have been experiencing more hypersensitivity reactions.<br> Cancers such as ALL (29%), retinoblastoma (22.6%) neuroblastoma (19.4%) and brain tumor (12.9%) have&nbsp;been the highest among all kinds of treated cancers. Based on the severity of the reaction, nausea and abdominal&nbsp;cramps (41.9%), skin changes, including flushing, hives and pruritus (35.5%), skin and lips angioedema (22.6%)&nbsp;had the highest prevalence.<br> Conclusion: The results showed that in more than half of the studied samples hypersensitivity reaction started&nbsp;in less than 10 minutes after drug administration. Most drug reaction is to vincristine, cisplatin, methotrexate,&nbsp;AraC (cytarabine) and carboplatinum and the majority of reactions have occurred after phase3 of chemotherapy&nbsp;that is comparable with previous studies.</p> Drug hypersensitivity reactions, Chemotherapy, Children 8 11 http://ijca.iums.ac.ir/browse.php?a_code=A-10-1-49&slc_lang=fa&sid=1 Ahmad Bahrami 1003194753284600396 1003194753284600396 Yes Iran University of Medical Sciences, Tehran, Iran. Mohammad Faranoush 1003194753284600397 1003194753284600397 No University of Medical Sciences, Tehran, Iran. Alireza Ghanbarian 1003194753284600398 1003194753284600398 No Iran University of Medical Sciences, Tehran, Iran