Hemoglobin 70g/L means that the concentration of hemoglobin in the peripheral blood is 70g/L. It is a moderate anemia, which may be related to insufficient or reduced erythropoiesis, excessive destruction of erythrocytes, and blood loss. 1.Insufficient or reduced erythropoiesis. (1) Hematopoietic cell abnormalities leading to anemia, such as leukemia, myelodysplastic syndromes, multiple myeloma, and so on. (2) Deficiency of hematopoietic substances, such as folic acid and/or vitamin B₁₂ deficiency causing megaloblastic anemia, and deficiency of folic acid and/or vitamin B₁₂ leading to impaired intracellular DNA synthesis. (3) Iron deficiency, such as decreased iron intake and impaired absorption. (d) Excessive iron loss, e.g., gastrointestinal bleeding, peptic ulcer, and various other disorders that cause chronic blood loss. (2) Excessive destruction of red blood cells. Hemolytic anemia such as impaired bead protein production anemia. 3. Blood loss. Including acute and chronic blood loss. Chronic blood loss is the most common cause of anemia, such as bleeding hemorrhoids, chronic gastrointestinal bleeding or patients with excessive menstrual flow. Once the patient has a hemoglobin of 70g/L, he or she needs to actively identify the cause under the guidance of the doctor and follow the doctor’s instructions for treatment.