What is the cause of some red urine in adults? This is what is clinically known as carnal hematuria. Hematuria can be caused by a variety of diseases, the most common of which may be a urinary tract infection. Hematuria from a urinary tract infection will be accompanied by symptoms of frequent, urgent or painful urination. It may be a urinary stone. Hematuria caused by urinary stones is accompanied by back pain or other painful symptoms. Another type of hematuria that is less common but needs special attention is hematuria caused by urinary tract tumors. Inside urinary tract tumors, such as renal pelvis cancer, ureteral cancer or bladder cancer, may cause hematuria. Therefore, in addition to routine urine examination, further urinary ultrasound or urological CT examination is needed to further clarify which disease is responsible for hematuria.