An infant of about 3 months old suddenly does not like to take milk but can drink some water. First, problems such as fever, diarrhea, vomiting or bad spirits should be ruled out. If there is nothing wrong, the possible reason is too much milk. It turns out that infants less than 3 months old cannot fully absorb the protein in formula milk. Even when milk is eaten in excess, it does not cause more protein absorption and increase the burden on the liver and kidneys. However, by 3 months of age, the ability to absorb protein from milk increases, thus increasing the workload of the liver and kidneys, which can cause “fatigue” over time. The appetite is reduced and the baby does not like to eat milk. For such babies, milk can be thinned out or fed when the baby seems to be sleeping. When the baby is temporarily fed with less milk, as long as he or she drinks enough water, there is usually no problem. After 10 days and a half months, when the liver and kidneys have rested sufficiently and recovered their functions, the baby will like to eat milk again.