The rise of platelets to 900 x 10⁹/L after chemotherapy in acute myeloid leukemia may be due to excessive gastrointestinal reaction, stimulation by hormonal drugs, and infection, and treatment should be chosen according to the specific cause. For example, if the gastrointestinal reaction (nausea and vomiting) is too severe, ondansetron can be given for relief. 1. Excessive gastrointestinal reaction: nausea and vomiting after chemotherapy, the body loses a lot of water, which in turn causes blood concentration in the whole body. You should replenish water in time, eat a light diet, and use metoclopramide, ondansetron and other medicines to relieve nausea and vomiting under the guidance of your doctor. 2. Stimulation of hormonal drugs: chemotherapy drugs are generally added to the glucocorticoid drugs, this type of drugs have greater side effects, the use of which will cause platelet elevation, it is recommended to consult a doctor in a timely manner, under the guidance of the doctor to adjust the chemotherapy program. 3. Infection: After chemotherapy, the body’s immunity decreases, and it is easy to be infected by bacteria and viruses, which leads to platelet elevation. First of all, chemotherapy should be stopped and treatment should be carried out according to the type of infection. If the infection is bacterial, antibiotic drugs can be used for treatment, such as penicillin. If the infection is viral, antiviral drugs such as ribavirin can be used. If platelets rise to 900×10⁹/L after chemotherapy for acute myeloid leukemia, it is recommended to consult a doctor in time to clarify the cause of the disease with the help of the doctor and to carry out targeted treatment or therapy.