Myelosuppression is a common toxic reaction to most chemotherapeutic agents. Most chemotherapeutic agents can cause varying degrees of myelosuppression, resulting in a decrease in the number of peripheral blood cells, which are composed of multiple components, each of which plays an indispensable role in the human body, and a decrease in any one of these components will cause a corresponding side effect in the body. Currently, due to the increasing scarcity of medical resources, more and more patients are receiving daytime chemotherapy or being discharged immediately after chemotherapy. This results in patients having to recuperate at home during the chemotherapy interval, and it is crucial for patients during the chemotherapy interval to cope with myelosuppression, a common toxic side effect. Juan Myelosuppression is a decrease in the activity of blood cell precursors in the bone marrow, that is, a decrease in white blood cells, absolute neutrophils, hemoglobin, and platelets. Because the average survival time of neutrophils is the shortest, about 6-8 hours, myelosuppression is often first manifested as a decline in white blood cells; the average survival time of platelets is about 5-7 days, and their decline appears later and lighter; while the average survival time of red blood cells is 120 days, which is less affected by chemotherapy, and the decline is usually not obvious. The first and most common bone marrow suppression after chemotherapy is a lower than normal white blood cell count, which is also due to the “lifespan” of white blood cells, which usually lasts 3-7 days, so the decrease in white blood cells mostly occurs about 5 days after chemotherapy. Chemotherapy patients are often asked to have their blood checked every 2-3 days after discharge from the hospital. Patients with decreased white blood cells do not feel uncomfortable, but the decrease in white blood cells can induce infections or even life-threatening diseases. Patients who are weak or have reduced food intake after chemotherapy have a high possibility of severe decrease in white blood cells or serious infections, so it is important to closely observe the changes in blood count. Therefore, if the absolute value of white blood cells, neutrophils, or total platelet count is below the normal range, not only should symptomatic whitening treatment be given, but also regular blood tests should be conducted every 1-2 days. For breast cancer patients receiving biweekly chemotherapy regimen (intensive chemotherapy regimen), due to the short interval of chemotherapy, in order to ensure that chemotherapy can be administered as scheduled, even if the white blood cells are normal, it is necessary to perform preventive whitening therapy. Blood tests should also be performed as described above. In addition to the biweekly regimen, some chemotherapy regimens with strong myelotoxicity are also recommended to be treated with prophylactic leukostasis in the same way as before. In order to avoid the occurrence of severe myelosuppression, continuous leukostasis treatment is recommended and must not be interrupted by oneself, resulting in serious consequences. White blood cells below 3.0*109/L should be treated with leukostasis, and leukostasis can be stopped when the white blood cells rise to >10.0*109/L. Continuous leukostasis is required for less than the above standard. The white blood cells will drop again after stopping the white-lift treatment, therefore, it is still necessary to recheck the blood routine every 3 days after stopping the white-lift treatment. Please do not be alarmed and stop the treatment without authorization. Please continue to complete the course of Boosting treatment as described above and drink more water, the white blood cells will return to normal after stopping the treatment. Patients with pain can take oral “ibuprofen” or “acetaminophen” (trade name: Piriton or Sanliacin) for pain management. After chemotherapy, patients should avoid going to crowded places because the decrease of white blood cells, the defender of our body, will lead to a decrease in the body’s ability to defend itself against external bacteria or viruses, which will greatly increase the chance of infection. Fever caused by a decrease in leukocytes or neutrophils after chemotherapy should not be underestimated, because the body’s resistance is reduced and a small infection can be serious to life-threatening, so if you have a fever, please go to the hospital immediately to check blood count and use anti-infection and whitening treatment (the specific treatment should be left to your doctor). Another indicator in the blood routine that should be concerned after chemotherapy is is the platelet count. The main function of platelets is to clot and stop bleeding and repair broken blood vessels. Platelets have an average lifespan of 7 to 14 days, and when the body bleeds from an injury, platelets will swoop in droves to close the wound in seconds to stop the bleeding. Decreased platelets can lead to abnormal blood clotting and may induce bleeding (e.g., bleeding gums, nosebleeds, subcutaneous bleeding, etc.). Platelets below 80.0*109/L require routine blood tests every 2 days. If platelets are below 70.0*109/L, it is recommended to start continuous daily use of platelet-raising injections until platelets recover to above 80.0*109/L. Platelets are small pieces shed from the megakaryocyte mass in the bone marrow, so after platelet-raising treatment is given, megakaryocytes need to mature and release first, and then platelets will be produced, so the platelet recovery time is slightly longer, so please be patient and observe. If platelets fall below 50.0*109/L, there is a risk of inducing serious bleeding (gastrointestinal bleeding, brain bleeding, etc.) and you must contact your doctor immediately for emergency treatment at the hospital. Bone marrow suppression is a common toxic side effect during our chemotherapy treatment, and there is no need to panic when it occurs. If handled well, it can ensure that chemotherapy is completed on time and according to quality; if not handled well, it will not only affect chemotherapy on time, but also may have serious consequences of infection, sepsis and even life-threatening. Therefore, “low white blood cells” this “little thing”, but also have to be treated carefully.