Possible causes of red urine color: First, food and drug staining, such as oral rifampin can cause red urine color. Second, urinary tract infection, infection can occur when the urinary epithelium micro-damage, the emergence of meatus hematuria, in the color of red, but also may be accompanied by urinary frequency, urinary urgency, painful urination symptoms, mostly related to infection. Thirdly, urinary tumor, commonly found in elderly patients, and without any urinary system irritation symptoms in carnal hematuria, and without painful urination or urinary frequency and urgency, need to perform ultrasound to further identify. Fourth, urinary system injuries, such as trauma to the lower back or lower abdomen, can appear as kidney contusion or bladder contusion, and red urine can appear at that time or within 24 hours after the injury. If the injury is mild, the hematuria is transient, but if the injury is severe, the hematuria may persist and worsen progressively.