Hematuria refers to the entry of red blood cells into the urine and is mainly divided into microscopic hematuria and carnivorous hematuria. The most common causes of hematuria are urinary tract infections, urinary tract stones and tumors. Microscopic hematuria refers to elevated red blood cells found in the urine under a microscope, while corporeal hematuria refers to blood inside the urine as seen by the eye. Most of the patients found hematuria are carnal hematuria. There are many causes of carnal hematuria, and the common causes are as follows Urinary tract infection: such as cystitis, mostly accompanied by frequent urination, urinary urgency, pain in urination, small abdominal pain, serious blood clots, fever symptoms, the incidence of urinary tract infection is higher in women than in men. Urological stones: mainly stones damage the mucous membrane of the renal pelvis and ureter and cause bleeding, which also easily causes hematuria, and most of this condition is preceded by painful symptoms in the lower abdomen and followed by hematuria. Urological tumors: Most of the hematuria caused by tumors is painless, and most of them appear in the middle and late stages of tumors, such as kidney cancer, bladder cancer and prostate cancer. Secondly, urinary system injury can also cause hematuria, such as urethral rupture, bladder rupture, etc. In summary, there are many causes of carnal hematuria, which need to be combined with the patient’s medical history, accompanying symptoms, physical examination and corresponding auxiliary examinations to clarify the specific cause.