There is no fastest and most effective way to replenish calcium for infants, and calcium supplementation needs to be carried out for a period of time. Usually, you can increase the calcium content of the lotion, drink milk powder with high calcium content, and medication to replenish calcium, etc. The specific analysis is as follows: 1. Increase the calcium content of the lotion: If the baby is breastfed, the mother eats more food with high calcium content, which can increase the calcium content of the lotion, and the baby can drink breast milk to replenish calcium. 2. Drinking milk powder with high calcium content: If the baby is formula-fed, you can choose milk powder with high calcium content to supplement calcium. 3. medication to supplement calcium: you can also through the drug to supplement calcium, under the guidance of the doctor to use calcium carbonate D3 granules, need to pay attention to the side effects of the drug, such as constipation, belching and so on. It is recommended to give the baby appropriate sunshine, which is conducive to the absorption of calcium.