Hematology is a department that diagnoses and treats common diseases of the blood cells as well as the hematopoietic system. Diseases commonly seen in hematology: i. Erythropoietic disorders, including erythropoietic disorders such as true erythropoietic disorders. ii. Erythropoietic diseases, the most common of which are various types of anemia, including iron deficiency anemia, megaloblastic anemia, aplastic anemia, autoimmune hemolytic anemia, serotonin, and thalassemia. Hematologic malignant neoplastic diseases, including leukemia, lymphoma, multiple myeloma and myelodysplastic syndrome. Third, bleeding disorders, including allergic purpura, autoimmune thrombocytopenic purpura, hemophilia, disseminated intravascular coagulation, vitamin K deficiency, etc. Therefore, hematologic disorders include many types and often require further examination in the hematology department.