High creatinine and high urea nitrogen indicate damage to kidney function, and the cause of kidney function damage should be actively investigated at this time. Kidney function damage can be caused by the following reasons: a. Glomerulonephritis, a disease involving autoimmunity in the human body, is a kind of kidney inflammation, if the disease is not well controlled further progress, and then cause creatinine, urea nitrogen elevation, kidney function damage. Second, diabetes, if poorly controlled can cause glomerulosclerosis, and then diabetic nephropathy, causing damage to kidney function. Third, the factors of drugs, if patients take drugs improperly, can cause acute damage to the glomerulus and renal tubules, and then appear acute increase in creatinine and urea nitrogen. Fourth, hypertension, which can aggravate atherosclerosis, and then glomerular sclerosis, causing hypertensive nephropathy and renal function damage.