The reason why breastmilk cannot be heated twice is that the process of repeated heating will lead to the loss and destruction of various nutrients in breastmilk, making the nutritional value of breastmilk decrease significantly. At the same time, the process of repeated heating will produce toxic and harmful substances, which is not good for the health of the baby’s gastrointestinal tract. If you want to store extra breastmilk for later feeding, you should consider the possible inconvenience of heating it up later when storing it, and store it in small packages as much as possible. When feeding the stored breast milk, try to control the amount of heated breast milk according to your baby’s daily consumption, preferably just enough to satisfy your baby’s consumption at one time. If the heated breast milk cannot be finished at one time, it should be discarded.