eng Science and Education Publishing American Journal of Cancer Prevention 2328-7314 2018-06-05 6 2 32 34 10.12691/ajcp-6-2-4 AJCP2018624 article Mehrdad Payandeh 1 Sakineh Ghorbani 2 Afshin Karami 3 Neda Veisi maheasman95@gmail.com 4 Ali Ghasemi 4 Mohammad Mehdi Maadikhah 4 Mojtaba Gorji 5 Mehrnoush Aeinfar 5 Fatemeh Yari 5 Masomeh Farhadi 5 Department of Hematology and Medical Oncology, Kermanshah University of Medical Sciences, Kermanshah, Iran Medical Bone Marrow Research Center, Imam Reza Hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran Department of Hematology, Shahid Beheshti University of Medical Sciences, Tehran, Iran Kermanshah University of Medical Sciences, Kermanshah, Iran Department of Hematology and Oncology, Lorestan University of Medical Sciences, School of Medicine, Khorramabad, Iran Hemorrhagic cystitis (HC) is a significant clinical problem that occurs after allogeneic transplantation and is often refractory. The patient was a 40-year-old man who had HC after two months of transplantation of allogeneic stem cells. Several treatments were used to improve the patient, but no improvement. At the doctor's proposal, 5 sessions of Ozone therapy were performed for the patient, After the completion of the sessions, the clinical symptoms associated with HC disappeared completely. This study shows that HC treatment with ozone therapy is an effective and tolerable method and does not have any clinical complications. http://pubs.sciepub.com/ajcp/6/2/4/ajcp-6-2-4.pdf hyperbaric oxygen therapy hemorrhagic cystitis allogeneic transplantation