Low white blood cell count of gastric cancer patients may be caused by treatment, bone marrow invasion, which needs to be treated with high vitamin food or white blood-boosting drugs according to the cause. Clinically, most of the patients with low white blood cell counts are caused by radiotherapy and chemotherapy, and those with small reduction usually do not need special treatment and can recover naturally after treatment; if the situation is serious, they need to use white blood cell-boosting medications, such as vitamin B4, granulocyte colony-stimulating factor, etc., and the treatment can be suspended if necessary. For the situation that stomach cancer has metastasized to bone marrow and caused low white blood cell count, it is necessary to carry out local and systemic anti-cancer treatment to inhibit tumor growth and restore bone marrow hematopoietic function, so as to improve the situation of low white blood cell count, and the above mentioned white blood cell-boosting medicines can be used together if necessary. Low white blood cell count will affect the immunity of the patient, and the treatment should be adjusted under the guidance of doctor.