Indications for bone marrow aspiration are: i. For patients who show clinical symptoms of anemia, infection or bleeding, but whose etiology is unclear, bone marrow aspiration can be used to confirm the diagnosis. Second, for patients with previously diagnosed leukemia multiple myeloma and other diseases, after a period of treatment, in order to judge the effect of treatment, bone marrow aspiration can be performed to determine how effective it is. For patients with unexplained fever, enlarged liver and spleen, and lymph nodes, bone marrow aspiration can also be performed to find the cause of the disease. Fourth, in order to do bone marrow transplant matching, bone marrow aspiration can also be done to extract the bone marrow cells from them for bone marrow matching. The contraindications of bone marrow aspiration are: i. For patients with diseases with obvious bleeding tendency, try not to do bone marrow aspiration, such as patients with hemophilia, they cannot do bone marrow aspiration. Second, if the patient’s vital signs are unstable, or when his life is in danger at any time, or when he is irritable, bone marrow aspiration should not be done at this time.