Cod liver oil is a fat extracted from the liver of shark, cod, etc. It is used to prevent night blindness and rickets. It contains mainly vitamin A and vitamin D. Infants taking cod liver oil can replenish vitamin A and vitamins, promote metabolism, boost immunity, fight radiation and cancer, cleanse blood vessels, and promote fat metabolism. Vitamin A is useful for maintaining normal visual function, immune system and reproductive health. Vitamin A deficiency can lead to symptoms such as dry eyes or night blindness and anemia. Vitamin D helps ensure that the body absorbs and stores calcium and phosphorus, and a deficiency in vitamin D deficiency can lead to rickets and osteochondrosis. Babies grow and develop fastest in the first 2 years after birth and need a lot of various nutrients. The amount of vitamin A and D in breast milk and cow’s milk are relatively low, and breast milk and cow’s milk cannot meet the child’s needs for vitamin D and vitamin A. Doctors generally recommend that babies start supplementing with cod liver oil half a month after birth, starting with one drop per day and then gradually increasing to a maximum of five drops. Premature babies, twins, or newborns with digestive tract diseases should add t cod liver oil from the second week of life, 5 drops per day, and then change to 3-5 drops after one month. after 2 years of age, the amount of cod liver oil is gradually reduced.