The human body has two kidneys, located on the back wall of the abdomen, on both sides of the spine, which is located about 10cm-15cm above the belt, commonly known as the “lumbar eye” place. Generally speaking, the average size of a normal adult male kidney is 11cm x 6cm x 3cm, and the size and weight of a female kidney is slightly smaller than that of a male of the same age, with an average weight of about 150 grams for men and 135 grams for women. We know that the main function of the kidney is to produce urine, and the part that forms primary urine through filtration is the glomerulus. The glomerulus accounts for about 9% of the volume of the renal cortex and 5% of the weight of the kidney. The length of glomerular capillaries in adults is measured to be about 13 km, of which the area with filtration is 1.6 m2. The kidney is like a 24-hour “cleaning plant” and is the main excretory organ of the body. It is the main excretory organ of the human body. It constantly filters and washes the blood, expelling waste and excess water from the body to form urine. If the kidneys become diseased, it is impossible for people to maintain a normal life. Unfortunately, most people are not even aware of the significance of the kidneys in maintaining health and life until they become ill. In fact, the kidneys have very important physiological functions. Function 1: Removal of metabolites and excess water. The kidneys are like a filter, about 1500-1800 liters of blood are filtered through the kidneys every day to produce about 180 liters of primary urine, which contains amino acids, glucose, vitamins, electrolytes and waste products, but all of them are absorbed back again by the renal tubules except for the waste products, and the final urine excreted is only about 1.5 liters per day on average. Function 2: Maintain the balance of water, electrolytes and acid-base in the body. The kidney can regulate organic substances such as protein, glucose and inorganic salts such as sodium, potassium and chloride in the body, so that they exist in the body in a certain proportion and concentration, and play a role in maintaining the normal life activities of the human body. Function 3: Produce a variety of bioactive substances. The kidney can produce renin, erythropoietin, prostaglandin, vasodilator, kinin and 1-hydroxylase, etc. Among them, the active substances including renin, prostaglandin and vasodilator can regulate blood pressure and water and salt metabolism; erythropoietin can stimulate the bone marrow to produce red blood cells, which have the role of carrying oxygen, and anemia will occur when the quantity is insufficient. It is because the kidneys have these important roles, once the kidneys do not work properly, can not get rid of the waste and excess water in the body, these metabolic waste has nowhere to go, it will accumulate in the body, a serious health hazard.