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). Jaundice causes yellowing of the skin or whites of the eyes. It's normal for the red blood cells to break down, although the bilirubin formed doesn't normally cause jaundice. 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. There is a condition that's commonly referred to as breast milk jaundice, although no one knows what actually causes it. To diagnose it, the baby should be at least a week old, gaining weight well with breast feeding, having lots of bowel movements, and clean urine. In some cases, infections in the baby’s urine, under functioning of the baby’s thyroid gland, and other rare illnesses 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, does breast feeding need to be stopped even for 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.