I don't know if I agree with "breastmilk jaundice" giving bilirubins as high as 20-30 (340-510 micromoles/l) for several months. That must be distinctly rare and I would really worry about such levels. Such a baby would not be yellow, he would be orange. I disagree though with the idea that the babies should be taken off the breast for 48 hours to "prove the diagnosis". Any physician worth his salt can distinguish between the baby with "breastmilk jaundice" and "something else". In the first place a baby with biliary atresia, by one month of age, has a big liver and spleen. Secondly, the simple question to the mother "what colour is the baby's urine?" will suffice to rule out liver disease. The urine of the baby with liver disease is brownish, and no well gaining exclusively breastfeeding *healthy* baby has brownish urine--it is as clear as water. In our clinic we will routinely bag a baby on arrival in case urine is needed (they are rarely needed, however). A dipstick is available that tests for bilirubin in the urine, or you can just look at the urine against the light. Urinary tract infection is supposed to be a cause of prolonged and elevated bilirubin, but I have seen only one in 14 years of doing a breastfeeding clinic which really convinced me that the bilirubin was elevated because of a urinary tract infection, and even then, the baby was gaining poorly, so that the elevated bilirubin could have been due to poor intake. Congenital hypothyroidism should be ruled out, as it usually is by the neonatal screen, but you won't find too many, since it occurs in only 1:6000 live births. There are some really rare enzyme deficiencies of the liver which cause elevated bilirubins, but it is madness to test for these in a healthy happy growing...okay, yellow baby. Jaundice is normal in exclusively breastfed well gaining babies, for weeks and even months, though it is usually only noticeable if you look carefully. What is not normal is the absence of jaundice in artificially fed babies (formula feeding anicteris). Physicians should rather encourage women with babies with *hypobiliribinemia* due to artificial feeding to take the babies of the formula for a couple of days and put them on the breast so that the bilirubin rises into the normal range. Jack Newman, MD, FRCPC Toronto, Canada