Bilirubin is the primary pigment found in bile, a product of the breakdown of red blood cells. Excess bilirubin produces jaundice, and in extreme cases (in babies) will cause kernicterus.

Although its molecule may look complicated:

               H-O   H  H   O-H
                 |  /    \  |
         C     O=C-C      C-C=O
         \\       / \    / \
          \\     H   \  /   H
 H         / H       /  \       H  H      H
  \ _____ /   \ ____/    \_____/    \____/
   |-----|    ||    |    |    ||    |    |
   |     |    ||    |    |    ||    |    |
  / \   /\\  / \   / \  / \   / \  //\  //\   H
 /   \ /  \\/   \ /   \/   \ /   \//  \//  \ /
O     N          N           N          N    O
|     |          |           |
H     H          H           H

you should notice, after looking at the heme molecule, that a bilirubin is simply a heme that has lost its iron atom, and been broken at one spot.

Bil`i*ru"bin (?), n. [L. bilis biel + ruber red.] Physiol.

A reddish yellow pigment present in human bile, and in that from carnivorous and herbivorous animals; the normal biliary pigment.

 

© Webster 1913.