Urine bleeding is often clinically manifested as hematuria of the naked eye. Hematuria of the naked eye is a common abnormal manifestation of urine, and there are many causes of hematuria of the naked eye. Common causes include urinary tract infection, urinary tract stones, urinary tract tuberculosis, urinary tract tumors, chronic nephritis and oral administration of certain drugs. Urinary tract infections are common in young women, because women have a short urethra and are more likely to suffer from urinary tract infections if they are sexually active, and common causative bacteria include Escherichia coli and Proteus mirabilis. As bacteria colonize the mucosa of the urinary tract, they cause an inflammatory response, resulting in hematuria caused by dilated capillaries and bleeding, and in severe cases, hematuria caused by the naked eye. Larger urinary stones can not only directly stimulate the mucous membrane of the urinary tract, but also cause the attachment of bacteria in the urine to cause urinary tract infection, which further causes hematuria. Urinary tract tuberculosis is often complicated by pulmonary tuberculosis, mostly due to the decline of the patient’s immunity causing tuberculosis infection of the urinary system, tuberculosis mycobacteria cause tuberculous cystitis and ulcers, often resulting in the occurrence of hematuria, usually manifested as terminal hematuria. Urothelial tumor is also a common disease of urological tumor. Tumor often causes hematuria due to rupture, and painless carnal hematuria is a common clinical manifestation of urological tumor. In patients with chronic nephritis and nephrotic syndrome, the destruction of the glomerular filtration membrane often causes leakage of red blood cells from the circulating blood, resulting in hematuria. Patients taking certain drugs or food orally, such as rifampin, aminopyrine or carrot, the urine can often be red, but the urinary routine is usually normal, which is pseudohematuria.