The urine appears light red, the possible causes are the following: 1, food or drug staining caused by, when taking food containing red pigment or taking special drugs, such as rifampin capsules, can appear urine yellow staining phenomenon. At this time, no red blood cells are seen in the urine retention test, which is mostly due to food or drug staining; 2, when there are stones, inflammation, tumors in the urinary tract, can lead to local mucosal destruction bleeding, blood mixed in the urine, manifested as light red or bright red change. If the infection is combined with urinary frequency, urinary urgency, painful urination and other urinary tract irritation symptoms, urinary stones are mostly accompanied by pain in the lower back and abdomen. In case of urinary tumor, there is no specific symptom in the early stage, only the red color of urine, but when the tumor grows further and causes pressure on the surrounding tissues, it can produce painful symptoms. Ultrasound and CT examination of the urinary system are required for further differentiation.