Jaundice

Jaundice is when the body's tissues, such as the skin, turn yellow because too much bilirubin, the substance that gives them that color, builds up. It shows in the sclera, the white of the eye, which has a high affinity for bilirubin, meaning it traps it easily.

Bilirubin stays in the tissues only when there is a surplus, and a surplus can happen for two reasons: the body makes too much or does not get rid of it well. It is like a sink, which overflows if you open the faucet too far or if the drain clogs.

The failure can occur in any of the three phases of bilirubin's journey. In the prehepatic phase, before the liver, heme, a part of red blood cells, is converted into bilirubin when those cells age or are defective. In the hepatic phase, inside the liver, it is conjugated: glucuronic acid is attached to it, and that makes it soluble in bile. In the posthepatic phase, after the liver, it travels with the bile to the intestine.