If the jaundice has not gone down by 40 days, it is breast milk jaundice and usually does not matter. If it is pathologic jaundice, it is important. If the jaundice at 40 days is due to breast milk jaundice, i.e. jaundice appears 3~5 days after birth, peaks at about 2 weeks and then subsides, and may continue for 4~12 weeks if breastfeeding is continued, then it is usually not important. Usually, breast milk jaundice subsides after 72 hours of cessation of breastfeeding, and no treatment is needed. If pathological jaundice is present, it is important that the jaundice has not subsided in 40 days to prevent serious condition causing kernicterus or even death, parents need to pay attention to it. Usually, pathological jaundice appears within 24 hours after birth, the jaundice lasts for a long time and the serum-conjugated bilirubin is more than 34 μmol/L. It is recommended to treat jaundice that has not subsided at 40 days. It is recommended that those whose jaundice has not subsided by 40 days should consult a doctor for prompt examination, so that the cause of the disease can be clarified and treatment can be prescribed to make the jaundice subside. Pay attention to the proper diet and go out in the sun more often. Jaundice is not limited to two types, breast milk jaundice written in a reasonable and justified can, undeniable this situation in the clinical is there.