If there is blood in urine and stool, it is recommended to go to the hospital for examination to clarify the causes, the possible causes are as follows: 1. The presence of urinary tract tumor, tumor metastasis invading the intestine, resulting in blood in urine and stool, which can be accompanied by pain or accompanied by abnormal defecation and other changes, such as bladder cancer invading the rectum or colon, or kidney tumor invading the colon, can cause blood in urine and stool. It is recommended to conduct CT examination of the urinary system to rule out the existence of urinary tract tumor metastasis. 2. Recto-vesical fistula, often seen after bladder surgery or intestinal surgery, which leads to bladder and rectum communication, can cause bleeding during urination or defecation, and can be accompanied by intestinal contents or secretions during urination, such as pus odor or stool during urination, often seen after pelvic surgery, such as bladder surgery or colon surgery. It is often seen after pelvic surgery, such as bladder surgery or colon surgery.