Cyclosporine is one of the main drugs used for the prophylaxis of graft versus host disease in bone marrow transplanted patients. Hypersensitivity reaction to intravenous cyclosporine is rare and might be due to its vehicle polyoxyethylated castor oil, Cremophor EL. The exact mechanism is unknown, but IgE and IgG antibodies, complement, and histamine release have been considered to play a role in the development of this reaction. Here, we describe a case of anaphylaxis to intravenous cyclosporine, which was developed in a 19‑year‑old Iranian female with acute myeloid leukemia who underwent allogeneic bone marrow transplantation from her sister. The corn oil‑based soft gelatin capsule (Sandimmune®) was substituted with no reaction. Our observation along with the previous reports confirms the role of Cremophor EL in hypersensitivity reaction to cyclosporine, according to which, modifying the formulation of the intravenous (IV) form could be the solution for this problem.