WebMD explains that a pigment known as urochrome is what gives urine its yellow color. MedlinePlus states that urine is typically straw-yellow in color, but it can turn a dark yellow or orange color due to B complex vitamin intake, carotene intake, or the use of certain medications, including laxatives, phenazopyridine, rifampin and warfarin.
MedlinePlus explains that urine of a dark yellow or orange color is not generally a cause for concern and has benign causes. The government resource recommends visiting a doctor if an individual experiences an unexplained change in urine color or if there is blood in the urine. Another potential cause for concern is pink, red or smoky-brown urine that is not the result of drug or food intake. The cause of urine of any of those colors may be hemolytic anemia, a kidney condition or a urinary tract injury. Clear, dark-brown urine is symptomatic of acute viral hepatitis and cirrhosis, both of which are liver disorders that require medical attention.
MedlinePlus states that urine can also appear in shades of green or blue, usually due to particular medications or artificial colors in food and drugs. Doctors examining patients with abnormally colored urine can use a number of tests to uncover the cause, including blood tests, urinalysis and ultrasounds of the kidneys and bladder.