Patients with kidney disease, especially in the advanced stages of the disease, develop anemia, which worsens with the deterioration of renal function. In advanced renal disease, the renal parenchyma is severely damaged, resulting in a decrease in erythropoietin production in the kidney and a decrease in the stimulation of the bone marrow hematopoietic system by erythropoietin, resulting in decreased erythropoietin production and anemia. In chronic renal failure, kidney function is severely impaired, and the amount of metabolic waste products excreted in the urine is reduced and their concentration in the blood is increased, which accelerates the deterioration of red blood cells and shortens their life span, leading to anemia. Patients with chronic renal failure have a low protein diet for a long time, which can reduce protein synthesis in the body, but a large amount of protein is lost in the urine, and this, together with anorexia and poor absorption in the small intestine, leads to a lack of nutrients in the body and insufficient intake of hematopoietic materials such as iron, folic acid and protein, resulting in anemia due to a lack of nutrients in the body. In uremic patients, guanidine and phenolic substances in the blood cannot be excreted in the urine, which not only cause abnormal blood clotting function but also increase capillary fragility. Therefore, patients with uremia often suffer from nosebleeds, gum bleeds, subcutaneous bleeds and gastrointestinal bleeds, and this chronic blood loss eventually leads to severe anemia. Because anemia in kidney disease is caused by renal parenchymal lesions, it is medically called renal anemia, which is iron-deficiency anemia, so these patients can take iron supplements to correct the anemia.