The main causes of blood in urine in men are the following: First, blood in urine caused by inflammation of the urinary system, if blood in urine is accompanied by swelling of the face and body, increased blood pressure and other symptoms, it may be acute nephritis, if blood in urine is accompanied by poor urination and pain in the urethra, it is mostly inflammation of the prostate. Second, cystitis causes blood in urine, such as blood in urine with severe urinary frequency, urinary urgency, urinary pain, most of them are acute cystitis, so the most common symptom of cystitis is that there is no feeling, the naked eye can see the bloody urine. Third, blood in urine caused by kidney or ureteral stones, blood in urine accompanied by lumbago, sometimes severe paroxysmal lumbago and abdominal pain will occur. Fourth, blood in urine caused by urological tumors, if blood in urine is accompanied by longer periods of urinary frequency, urinary urgency, urinary pain in patients, the possibility of renal tuberculosis is greater, age above 40 years old, blood in urine and pain without obvious symptoms, may be infected with urological tumors. The above questions are for reference only, please refer to the doctor’s face-to-face guidance for specific medication and treatment.