Iron supplementation for children is usually taken half an hour after a meal because a few children have gastrointestinal reactions to iron, such as nausea, vomiting, stomach upset, diarrhea, and other reactions. If the baby is a regular preventive iron supplement, a full-term baby can start taking iron supplements 4 months after birth, and it is best to continue supplementation until 1-2 years old. It is best to feed eggs and dairy foods separately during this period, because egg yolks and cow’s milk contain high phosphorus complexes that can prevent iron absorption. It is best to take vitamin C at the same time as iron supplementation because it improves the absorption rate of iron, and vitamin C is best taken before meals because it can better absorb iron from food and medicine after taking vitamin C.