Brown urine may be caused by physiological factors, urinary tract infections, urinary tract stones, urinary tract tumors, blood system diseases and other factors. 1. Physiological factors: for example, when a woman is in her physiological cycle, menstrual blood enters the urine, which will cause the color of the urine to become brown, and after the physiological cycle, the color can return to normal on its own. 2. Urinary infections: for example, urethritis, cystitis, when the infection is particularly serious, resulting in bladder mucosal damage and bleeding, will make the urine color brown, accompanied by frequent urination, urinary urgency, urinary pain and other symptoms. 3. Urinary stones: when there are stones in the urinary tract system, it may cause damage to the urinary tract system, resulting in bleeding, which will make the urine color change to brown, such as ureteral stones, bladder stones, etc., which may be accompanied by urinary difficulties, pain in the lower back and abdomen and other symptoms. 4. Urinary system tumor: the presence of urinary system tumor, tumor local tissue necrosis and bleeding, can lead to the urine color becomes brown, may also be accompanied by abdominal distension, difficulty in urination and other symptoms, such as bladder tumors, urethral tumors and so on. 5. Blood diseases: for example, leukemia, hemophilia, aplastic anemia, etc., may cause local bleeding, which will lead to urine color change to brown. Brown urine, and exclude physiological factors, it is recommended to go to the hospital urology department for examination and treatment in a timely manner to avoid delays.