Urea nitrogen is the end product of protein metabolism, high urea nitrogen can be seen in a large number of high-protein food, generally no symptoms; can also be seen in gastrointestinal bleeding, heart failure, renal insufficiency, etc., may appear the symptoms of the primary disease, such as vomiting blood, black stools, chest tightness, suffocating breath, urine or even anuria. Elevated urea nitrogen can be seen in physiological conditions such as eating a large amount of high-protein food, at this time no special treatment, light diet, regular review can be. Pathological conditions such as gastrointestinal bleeding, heart failure, renal insufficiency, etc., at this time there may be nausea, vomiting, abdominal distension, loss of appetite, vomiting blood, black stools, etc.; chest tightness, wheezing, coughing, hemoptysis, etc.; hematuria, foamy urine, edema, hypertension, oliguria or even anuria. Targeted treatment is needed according to the specific cause of the disease. When the patient found that the urea nitrogen is elevated should be timely regular hospital consultation, under the guidance of the doctor to further improve the examination, to clarify the cause of the disease, for standardized treatment.