© 2022 Société française de transfusion sanguine (SFTS)Methods: SARs were examined occurred within 1 hour after initiating HSC product infusions in all HSCT done in Turkey's Anadolu Medical Center Hospital accredited for HSCTs between 2013 and 2015, targeting 315 patients. Results: SARs were carefully evaluated in this study based on a comparison of the amount of stem cells infused, age, frozen sample (FS) / non-frozen samples (NFS) between HSCs sources. Rate of SARs is significantly higher in FS infusions supports the hypothesis that DMSO plays an important role in the development of SAR. Conclusion: The rate of SARs is significantly higher in infusions given using FSs confirms the hypothesis that the preservative agent DMSO plays an important role in the development of SAR. Our study provides guidance for future studies on the necessity of reducing the amount of DMSO in the HSCT product and using other alternative freezing agents instead of DMSO.