Jaundice is a result of buildup in the blood of the
bilirubin, a yellow pigment that comes from the
breakdown of older red blood cells.  It's normal
for the red blood cells to break down, although
the bilirubin formed doesn't normally cause jaundice
because the liver will metabolize it and then get
rid of it in the gut.

However, the newborn baby will often become
jaundiced during the first few days due to the
liver enzyme that metabolizes the bilirubin becoming
relatively immature.  Therefore, newborn babies 
will have more red blood cells than adults, and
thus more will break down at any given time.

Breast milk jaundice
There is a condition that's commonly referred to 
as breast milk jaundice, although no one knows
what actually causes it.  In order to diagnose it,
the baby should be at least a week old.  The baby
should also be gaining well with breast feeding
alone, having lots of bowel movements with the
passing of clean urine.

In this type of setting, the baby has what is 
referred to as breast milk jaundice.  On occasion,
infections of the urine or an under functioning
of the baby's thyroid gland, as well as other
rare illnesses that may cause the same types of
problems.

Breast milk jaundice will peak at 10 - 21 days,
although it can last for 2 - 3 months.  Contrary
to what you may think, breast milk jaundice is
normal.  Rarely, if at all ever, does breast
feeding need to be stopped for even a brief
period of time.

If the baby is doing well on breast milk, there 
is no reason at all to stop or supplement with
a lactation aid.