What causes bilirubin buildup?

Bilirubin buildup happens when your body can't get rid of a yellow pigment that comes from old red blood cells.

Imagine you have a toy car, and after playing with it for a while, it breaks down. Your body does something similar with red blood cells, they wear out, and then they break down into parts, one of which is bilirubin, like the dust from your broken toy.

Your liver normally takes care of bilirubin by changing it so it can be removed through bile, kind of like how you clean up the dust from your toy car. But if your liver is tired or blocked, like a traffic jam on the road to the dump, bilirubin stays in your body and makes your skin and eyes look yellow, just like if all that toy car dust stayed inside your room!