Low red blood cells means that the number of red blood cells in peripheral blood is below the normal range, because the number of red blood cells in the peripheral blood of a normal healthy adult male is 4-5.5 million red blood cells per milliliter of blood, and the number of red blood cells per milliliter of blood of an adult female is 3.5-5 million, if the number of red blood cells is below the standard range, it belongs to low red blood cells, and low red blood cells are often clinically manifested as anemia The symptoms of low red blood cells are often clinically manifested as anemia. According to the degree of decrease in hemoglobin concentration, anemia is classified as mild anemia, moderate anemia, severe anemia and very severe anemia. Different treatments are needed depending on the cause of the disease.