Platelets below 20×10^9/L can be recovered after chemotherapy. Chemotherapeutic drugs kill cancer cells and at the same time damage normal cells with vigorous growth, so that the division and proliferation of hematopoietic cells are affected, resulting in lowering of white blood cells, platelets and hemoglobin, which is a common adverse reaction of chemotherapeutic drugs. In general, as long as the bone marrow hematopoietic system is not violated, generally after the end of chemotherapy, the bone marrow hematopoietic function will slowly recover and platelet counts will appear to rise. Platelets lower than 20×10^9/L are considered severe thrombocytopenia, and it is recommended to adjust the chemotherapy dosage according to the individual’s condition and conduct blood transfusion therapy under the guidance of the doctor.