It is recommended that infants take vitamin D after meals under the supervision of a physician, either by dropping the contents into the mouth or mixing it into milk powder. Vitamin D is fat-soluble. In order to prevent gastrointestinal symptoms such as vomiting, nausea and acid reflux caused by taking it on an empty stomach, it is recommended that it be taken half an hour after a meal, as the fat-soluble substances contained in milk or rice can promote the absorption of vitamin D. As infants have poorer swallowing ability and find it difficult to swallow the medication, they can cut the top of the vitamin D drops and melt its gelatinized skin, then mix it with water or milk powder to drink. Because breast milk contains less vitamin D, it is recommended that vitamin D supplementation be started a few days after birth and maintained until 2 years of age. However, it should be noted that vitamin D increase and hypercalcemia do not allow additional vitamin D supplementation. Therefore, a physician should be consulted before giving vitamin D to infants, and the specific dosage should be chosen under the guidance of the physician.