Jaundice is caused by the buildup of a yellow substance called bilirubin in the blood. Bilirubin is produced when red blood cells break down. The condition occurs when there is either an increased breakdown of red blood cells, a problem with the liver's ability to process bilirubin, or an obstruction that prevents bilirubin from being excreted from the body. There are three main categories of causes for jaundice:

• Prehepatic causes: Increased breakdown of red blood cells (hemolysis) leading to excess bilirubin production. This can be due to conditions like G6PD deficiency, hemolytic anemias, certain infections, or hereditary conditions like Gilbert's syndrome.
• Hepatocellular (liver) causes: Liver diseases or damage that impair bilirubin processing in the liver. Examples include viral hepatitis, cirrhosis, alcoholic liver disease, autoimmune liver diseases, certain cancers, and genetic liver disorders.
• Posthepatic causes: Obstruction of bile flow that prevents bilirubin excretion, such as gallstones, pancreatic cancer, bile duct strictures, or infections affecting bile ducts.

Thus, jaundice results from problems related to red blood cell breakdown, liver function, or bile duct blockage which leads to bilirubin accumulation and yellowing of skin and eyes.