If there is blood after urination, you need to observe whether the blood is located in the urethra, or mixed in the urine, and whether it is clotted, it is recommended to go to the hospital for further examination. The most likely causes: first, acute cystitis or urethritis, after urination can appear mixed with blood clots or bleeding performance, accompanied by painful urination, increased frequency of urination or small abdominal cramping pain; need to retain urine for routine examination, if the urine can be seen in the red and white blood cells or bacterial count is significantly higher, it suggests that the infection caused; second, bladder stones or urethral stones, stones irritate the local mucosa leading to If the presence of stones is confirmed, lithotripsy or lithotripsy is recommended; third, when posterior urethral infection occurs, such as inflammation of the bladder neck or inflammation of the posterior urethra, local bleeding may occur, and the patient may have pain in the perineal area and pain after urination It is recommended to conduct urethroscopy or urine culture examination to clarify whether there is infection of the posterior urethra or whether there is bleeding due to local mucosal damage.