If the urine appears to be pink, there may be bleeding and further examination is needed to clarify: 1. Infection of the urinary system. If the mucous membrane of the urinary tract is congested or eroded due to infection, the number of red blood cells in the urine may increase, causing the urine to be pink in color. 2. urinary tract stones. If there are stones in the kidney, ureter or bladder, it can cause the local mucous membrane to break down and bleed, and the number of red blood cells in the urine increases, which can also cause the urine to appear pink. 3, traumatic diseases. For example, trauma to the lower back and external genital area can cause the mucous membrane to break down and bleed, which can cause a pink color when urinating.4. Food or drug staining can also cause the urine to appear pink, such as oral medications, such as aminopyrine tablets or rifampin capsules, which can lead to changes such as light pink or red urine.