For insufficient vitamin B12 intake, exogenous supplements can be given, either oral vitamin B12 tablets or intramuscular vitamin B12 injections. At the same time, patients are advised to have their serum homocysteine checked, because vitamin B12 deficiency can lead to blood homocysteine deficiency, which can also cause the patient to become anemic, etc. If necessary, patients with severe anemia require blood transfusion therapy, which generally refers mostly to patients with anemia in which the hemoglobin is moderate to severe. For vitamin B12 deficiency, the first step is to find the cause. Clinically, it may be insufficient intake of vitamin B12, mainly due to the patient’s unreasonable diet structure with little green vegetables, or it may be a loss of vitamin B12, such as gastrointestinal diseases.