Infant vitamin AD drops are generally recommended to continue supplementation until about 2 weeks of age to effectively prevent a range of diseases caused by vitamin A and vitamin D deficiency, which varies from person to person. Usually, infants are fed mainly with breast milk or formula, in which the content of both vitamin A and vitamin D cannot meet the needs of growth and development. In the case of normal full-term infants, vitamin AD drops are usually given routinely 15 days after birth; in the case of premature infants, vitamin AD drops are usually given right after birth. It is good for preventing rickets, promoting tracheal and lung development, and regulating immunity. However, care should be taken to supplement vitamin AD drops under the guidance of a doctor and not in excess, so as not to cause acute poisoning. In daily life, parents are advised to let their infants get more sunlight appropriately, which is conducive to the synthesis of vitamin D and promotes the absorption of calcium.