Clots of coagulated blood inside the urine may be related to urinary system infections, urinary tract stones, urinary system tumors and so on. 1. Urinary system infection: when a serious infection occurs in the urinary system, such as cystitis, a large number of bacteria continue to multiply in the bladder. It may cause a large area of mucosa in a state of congestion and edema, if there is a large area of blood seepage. It is easy to cause blood stasis and form blood clots to be discharged with urine. 2. Urinary stones: sharp stones will cut through the ureter or urethral mucosa, causing bleeding in the urinary tract. When the bleeding is high, blood clots will easily appear, which will be discharged with the urine. 3. Urological tumor: such as renal pelvis cancer, when the surface of the tumor is ruptured, the patient may have hematuria. The hematuria will coagulate into blood clots inside the bladder, which will be discharged with urine when the patient is urinating. There are other reasons why there are clots in urine, so it is recommended to consult doctor in time, follow the doctor’s instruction to conduct relevant examinations, and deal with or treat the problem with the help of doctor.