We understand that every infant and young child needs to have adequate vitamin D intake during their growth and development, but how to supplement vitamin D depends on two aspects: 1. whether the child has adequate vitamin D intake in their daily diet and life, which means how the infant is fed (breast milk? Artificial formula? What kind of formula?) The amount of milk, outdoor activities, season and region, etc. 2. Individual differences of children, such as full-term babies? Premature baby? Low weight baby? Twin births? And his growth rate and genetic factors, etc. And exactly which vitamin D preparation to use? Parents are often faced with several choices online or in baby stores. There are several additional vitamin D preparations available: Icocin, which is an over-the-counter drug with a national drug code, has green gel pills for children under 1 year of age and pink gel pills for children over 1 year of age. Green gel pills contain 1500 units of vitamin A and 500 units of vitamin D. Pink gel pills contain 2000 units of vitamin A and This drug has been widely used in clinical practice for a long time and has been accepted and approved by a large number of doctors and parents. In addition, there are some health products that do not belong to the drug class, such as some parents use Akach, which is also known as shark liver oil, it contains vitamin A 900 units and vitamin D 300, so it is only for infants and children aged 0-1 years, and in winter for breast-fed children, whether the amount of vitamin D supplementation can meet the needs of infant growth and development, it remains to be dynamically observed. There is another kind called infant cod liver oil, which contains not only 1500 units of vitamin A and 150 units of vitamin D, but also a small amount of DHA and EPA, and this ratio is more suitable for the situation abroad. Through this talk, parents should understand that while giving their children vitamin D supplementation, it is advisable to consult with a professional pediatric clinical and child health practitioner as a comprehensive judgment is needed.