Blood in urine but no pain may be related to drugs, bleeding disorders, urinary tract tumors and so on. 1. drugs: some drugs can cause red urine because of metabolic reasons, such as bisacodyl ryanin capsules may appear red or brown urine after use, which is mistaken for hematuria. 2. Diseases with blood clotting abnormalities: such as hemophilia, when the kidneys are mildly impacted, it may also cause bleeding, showing painless blood in the urine. 3. Tumor of urinary system: the more common one is bladder cancer, and the typical symptom is painless and intermittent hematuria. When the tumor invades into the surrounding tissues, blood vessel rupture occurs, manifesting painless hematuria. Blood in urine but without pain can also be seen in other causes, it is recommended to consult a doctor in time, follow the doctor’s instructions for relevant examinations, and deal with or treat with the help of the doctor.