Bilirubin is a yellow compound that occurs in the body when red blood cells break down. It is produced in the liver and is a key component of bile, which helps in the digestion of fats. Bilirubin is usually processed by the liver and excreted in stool, giving it a brown color. High levels of bilirubin can lead to a condition called jaundice, where the skin and eyes turn yellow. This can indicate liver problems or other health issues. Monitoring bilirubin levels is important for diagnosing and managing various medical conditions.