If there are blood clots in the urine, the presence of bleeding in the urinary system is considered. There are many reasons for bleeding: 1. There may be stones in the urinary system. At the same time, there is pain in the area where the stone is located, such as lumbago, abdominal pain, etc. Further ultrasound examination is needed. 2. There are occupying lesions in the urinary system, such as benign and malignant tumors of the urinary system, which will bleed after the growth of the tumor, and the bleeding will clot in the ureter and bladder and be discharged out of the body, forming a blood clot. As in the case of tumors of the bladder, most of them form irregular blood clots. If it is a tumor of ureter, most of them are long strip-like or worm-like blood clots. Further CT examination of the urinary tract is needed to identify whether there is a tumor of the urinary system.3. Urinary tract infections can also cause blood clots, especially in acute congestive cystitis, which can result in blood clots due to extensive blood leakage from the bladder mucosa, along with accompanying symptoms such as urinary frequency, urinary urgency, painful urination and fever.