The possible causes of red urine are: 1. Taking drugs or food staining, such as rifampin capsules, aminopyrine tablets, purines or carrots, can lead to red urine, which is usually not accompanied by any abnormal urination, and does not contain red blood cells after routine urine examination. 2. 3. If there is an acute urinary tract infection, mucosal congestion and edema can also occur, resulting in red urine, accompanied by frequent and urgent urination or abdominal pain, back pain, fever and other symptoms. 4. If there is a tumor in the urinary tract, red urine can occur, and in the early stage, there is usually no obvious pain, and the urine is red throughout the whole process, and in the later stage, local pain symptoms can occur, and CT examination of the urinary system is needed for further identification.