The discharge of bright red blood clots in urine may be caused by urinary tract infection, traumatic diseases and tumors of the urinary system. 1. Urinary tract infection: If the patient has serious urinary tract infection, due to the stimulation of inflammation, the mucosa of the urinary tract may appear local congestion, edema, erosion, bleeding and other symptoms, when the blood stays in the urethra after coagulation, there may be the phenomenon of bright red blood clots in the urine. 2. Traumatic diseases: when there is a history of trauma to the patient’s urinary system, such as bladder injury, kidney contusion. Due to the damage of blood vessels, bleeding may occur, and when the blood accumulates and coagulates, it may be discharged with the urine, resulting in the phenomenon of bright red blood clots in the urine. 3. Tumor of the urinary system: such patients may have hematuria due to tumor invasion and necrosis. When the blood accumulates and clots in the urethra, the phenomenon of bright red blood clots in urine may also occur. Therefore, if the patient appears to have bright red blood clots discharged from the urine, he should go to the hospital in time for treatment, so as to avoid delaying the condition and causing adverse consequences.