Blood after surgery for renal stenoma may be normal phenomenon, and may also be caused by improper care, postoperative infection and other factors. 1. Normal phenomenon: during the surgery, due to the local damage, there will be bleeding after the surgery, just a small amount of bleeding, usually can recover on their own, will not cause too much impact. 2. Improper care: If you don’t have reasonable rest after the surgery and do some strenuous exercise, it may lead to tearing of the surgical incision site, which will easily lead to bleeding, and may be accompanied by pain, swelling and other symptoms. 3. Postoperative infection: after surgery, improper care may cause local infection, which may cause bleeding and may be accompanied by weakness, fever and other symptoms. Postoperative blood in renal stenoma may also be caused by other factors, if the bleeding is more or accompanied by other abnormal manifestations, it is recommended to go to regular hospitals for consultation and treatment in time.