Infants generally do not need to take extra calcium supplements, whether the baby is breastfed or formula-fed, but need to take vitamin D supplements under the guidance of a doctor. For babies who are exclusively breastfed, if breast milk is sufficient, the baby’s milk quantity is normal, and the calcium content in breast milk can meet the needs of the baby’s growth and development, they only need to insist on vitamin D supplementation, and generally do not need to take extra calcium supplements. If the baby is mixed-feeding or formula-fed, because the calcium in the formula has been matched well, there is generally no need for additional calcium supplementation. However, infants need to take vitamin D supplements under doctor’s supervision to regulate calcium and phosphorus metabolism. If infants show symptoms of calcium deficiency, they need to bring their babies to the pediatrician of the hospital in time to avoid delay in treatment.