Bone marrow aspiration is a bone marrow puncture examination; the appearance of adolescent bone marrow aspiration with active proliferation of nucleated cells, there may be physiological factors, such as normal physiological processes, etc.; there are also pathologic factors, such as acute leukemia, myelodysplastic syndromes and other diseases, and should be timely to seek medical attention to find out the reasons. 1. Physiological factors: under normal circumstances, due to the limited lifespan of blood cells, active bone marrow hyperplasia can replenish senescent blood cells, there will be active bone marrow nuclear cell hyperplasia, reflecting the basic hematopoietic function of the bone marrow, which is a normal physiological phenomenon. Therefore, there may be a situation that the bone penetration of adolescents has active nuclear cell proliferation. 2. Pathologic factors (1) Acute leukemia: it is a malignant clonal disease originated from hematopoietic stem cells, which will show the symptoms of overactive bone marrow and obvious proliferation of nucleated cells, reflecting that the bone marrow is hyper-hematopoietic. Therefore, there will be a situation that the bone penetration of adolescents with nucleated cell hyperplasia is active. (2) Myelodysplastic syndrome: a disease of pathological hematopoiesis of blood cells, with a tendency to transform into acute myeloid leukocytes, originating from hematopoietic stem cells, presenting abnormal proliferation of bone marrow cells and active bone marrow hyperplasia. Therefore, it may appear that adolescents with active bone penetration nucleated cell proliferation. If there is a case of active nucleated cell hyperplasia in adolescents, you should consult a doctor and make a clear diagnosis in time to avoid delaying the condition.