Low platelets caused by infections, etc. can be restored to normal value within 1~2 months after targeted treatment, while those caused by leukemia, etc. can only be restored after the disease has been cured, and there is no specific time for recovery. 1. Infection: If the platelet is lowered due to cold or bacterial or viral infection, most of the patients’ platelet index can be recovered within 1~2 months after targeted anti-viral and anti-bacterial infection treatment. Drugs include ganciclovir, levofloxacin and so on. 2. Leukemia: For platelet reduction caused by leukemia, radiotherapy, chemotherapy (cytarabine) and bone marrow transplantation are required, and the platelet index can be gradually normalized after the condition is fully recovered, but the specific recovery time cannot be determined. 3. Aplastic anemia: cyclosporine, anti-thymocyte globulin and other drugs need to be given in time, and the recovery time can be as long as half a year. Thrombocytopenia can also be seen in systemic lupus erythematosus, severe liver disease, etc. It is recommended to determine the specific cause of the disease, under the guidance of the doctor for targeted treatment.