Vitamin AD drops for newborns are used differently depending on the birth status of the newborn. Typically most newborns start vitamin AD 2 weeks after birth at 400 IU per day. Neonatal vitamin AD drops dosage usage, full-term babies and preterm babies, low birth weight babies, etc. slightly different, in general, most of the newborns are full-term babies, 2 weeks after birth to start vitamin AD supplementation, vitamin AD 400IU per day, until 2 years of age. Preterm infants, low birth weight infants, twin infants need to be supplemented with vitamin D starting 1 week after birth, daily supplementation of vitamin AD400IU plus vitamin D400IU, and after 3 months of supplementation change to a preventive amount, i.e., supplementation of vitamin AD400IU per day until the age of 2 years. In the process of vitamin AD supplementation, if there are signs of vitamin D deficiency such as excessive sweating, irritability, square skull, occipital baldness, ectropion of rib margins, etc. or if the examination reveals that the child is vitamin D deficient, it is necessary to increase the dosage of supplementation to prevent rickets. Newborns taking vitamin AD drops must be used under the guidance of a doctor, do not increase or decrease the use of medication, to avoid drug poisoning or insufficient dosage and other phenomena.