Jaundice, also referred to as icterus, is the yellow staining of the skin and sclerae (the whites of the eyes) by abnormally high blood levels of the bile pigment, bilirubin. The yellowing extends to other tissues and body fluids and also may turn the urine dark. Yellowing of only the skin also can be caused by eating too many carrots or drinking too much carrot juice.
The bile pigment, bilirubin, comes from red blood cells. When old red blood cells are destroyed by the body (a normal process), the oxygen-carrying molecule within the cells, hemoglobin, is released into the blood. The hemoglobin is rapidly converted to bilirubin in the blood. The bilirubin is removed from the blood by the liver, modified, and excreted into the bile. The bile flows into the intestine so that the bilirubin is eliminated in the stool. (It is bilirubin that gives stool its brown color.) Jaundice can occur whenever this normal process of destruction of red blood cells and elimination of bilirubin is interrupted. This occurs when there is abnormally increased destruction of red blood cells (hemolysis), liver disease that reduces the ability of the liver to remove and modify bilirubin, or obstruction to the flow of bile into the intestine.