Hemoglobin 99g/L is mild anemia. Hemoglobin 99g/L is mild anemia and is not serious. But whether hemoglobin 99g/L is serious or not depends not only on the number of grams of hemoglobin, but also mainly on the cause of the decrease in hemoglobin. For example, patients with iron-deficiency anemia are due to insufficient intake of iron, in this case, only by eating more iron-rich foods and taking appropriate iron supplements, most patients will be able to return to normal within a month or so, and there are no serious consequences. But the same hemoglobin 99g / L, is caused by malignant tumors of the digestive tract, the consequences of this case are very serious, if not timely treatment may affect the patient’s life safety. In the case of leukemia, hemoglobin 99g/L, in addition to anemia, the patient will have other symptoms such as infection, bleeding, etc. If not treated in time, often due to infection or bleeding and lead to death.