Azelaic acid phenylbutyrate is an oral antitumor drug, which belongs to a kind of alkylating agent. It can specifically block the replication and division of tumor cell DNA to kill tumor cells. It is commonly used clinically in the treatment of patients with Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, chronic lymphocytic leukemia, ovarian cancer, and some breast cancers. Nitrogen mustard phenylbutyrate is used in the treatment of different tumors, and its dosing method varies greatly. It has to be taken in different ways depending on the type of tumor. Like other anti-tumor drugs, Phenylbutyrate can have side effects such as gastrointestinal discomfort, nausea, vomiting, and loss of appetite. It also has obvious myelosuppressive effect, which is manifested by the decrease of white blood cells, platelets and red blood cells. Therefore, when taking benztropine mustard, there is frequent review of blood routine, and the dosage of benztropine mustard should be adjusted according to the number of blood cells.