Liver
The liver cannot metabolize toxins and waste so these bad things stay in the blood longer. One thing that builds up is a substance called bilirubin. When red blood cells die, the hemoglobin in them leaks into the blood. The hemoglobin becomes bilirubin (a yellow substance that makes bile yellow). The liver takes the bilirubin out of the blood and puts it into the bile. The bile goes into the intestines and then goes out with the waste from your body. If the liver is hurt, it does not remove the bilirubin, so the bilirubin stays in the body. This makes the person's body look yellow and is known as jaundice. So yellow eyes and yellow skin are symptoms of liver disease.