Possible causes of urine redness: first, due to extreme concentration of urine, such as urinary retention of patients who have not urinated for a long time, or the presence of less water, more sweating, more loss of body fluids and other factors, may lead to concentrated urine and lead to urine redness. Usually there are no symptoms such as frequent urination, urgent urination, painful urination, etc. After drinking more water or rehydrating properly, the color of urine can return to normal. Secondly, if there is a urinary tract infection, the urine color can be red and yellow. Because of the infection, the mucous membrane epithelium of the urinary tract is congested and edematous, so it will lead to a little blood oozing, and at the same time, it can be accompanied by an increase in urine pigment. It is usually accompanied by symptoms such as frequent urination, urgent urination and painful urination, which need to be further identified by routine urine examination. Third, if there are diseases such as hepatocellular jaundice or obstructive jaundice, they can lead to ruddy urine color. Because of these diseases, the bilirubin level in the blood may be elevated, and the level of conjugated bilirubin excreted from the urine will then be elevated, which will manifest itself as a red urine color. This is usually not accompanied by frequent urination, urgency, or painful urination. Ultrasonography of the liver and biliary system and liver function tests are required to further confirm the diagnosis.