Blood but no pain when wiping after urination may be caused by kidney stones, polycystic kidney, urinary tumor and other diseases. 1. Kidney stones: Kidney stones are mainly related to metabolic abnormalities, and climatic factors, urinary tract infections, dietary factors, medication factors and other reasons may also induce the disease. Patients will experience symptoms such as vomiting, irritability, nausea, etc. They will also experience hematuria, which may lead to blood when wiping after urination. 2. Polycystic Kidney: The cause of Polycystic Kidney may be related to genetic factors, gene mutation, kidney disease, long-term hemodialysis and other factors. Patients will have symptoms such as elevated blood pressure, hematuria, proteinuria and enlarged kidneys. 3. Urological tumors: Urological tumors include renal tumors, bladder tumors and so on, which can lead to hematuria, resulting in the situation that there is blood but no pain when wiping after urination. If the situation of wiping blood after urination without pain occurs, it is recommended to go to regular hospitals for examination to clarify the cause of the disease.