The kidneys are not the digestive system; they are part of the urinary system. As an organ of the human body, the kidney mainly eliminates excess water and toxins from the body, maintains water, electrolytes, acid-base balance and the stability of the internal environment. However, when the kidneys have problems and chronic renal failure occurs, especially into chronic renal failure and end-stage uremia, its can appear symptoms of the digestive system, such as nausea, vomiting, loss of appetite, peptic ulcers, and even gastrointestinal bleeding. Evidence-based medical statistics show that patients who have chronic kidney disease have a higher incidence of H. pylori than normal healthy people, and H. pylori is the main cause of chronic gastritis and peptic ulcers. Therefore, although the kidneys are not the digestive system, kidney disease can cause symptoms of the digestive system. Therefore, patients with digestive system symptoms, especially those with a history of nephritis and nephropathy, should have their kidney function checked to screen for digestive system symptoms caused by kidney failure.