Calcium is a very important substance for every stage of a child’s development, so it is necessary to take calcium supplements regularly. If a baby is breastfed, it does not need calcium supplementation within 6 months after birth if there are no symptoms, and the nutrients provided by a healthy mother’s breast milk are sufficient; after 6 months, the mother should add calcium-rich supplementary foods to the baby. After two years of age, children are prone to calcium deficiency due to the diversification of their diets, while the intake of dairy products decreases. In the case of insufficient calcium intake, the child should be given calcium supplements according to the principle of how much is missing. If a child is deficient in calcium, he or she will have conditions such as night sweats, late teething, frequent crying, late walking and easy cramping. You should go to the hospital in time and choose calcium supplement drugs for your baby under the guidance of the doctor. You should also pay attention to let your child drink more milk and increase the intake of soy products, fish, eggs, kelp, shrimp, fresh vegetables and other foods. If the sun is good, you can also take your child out in the sun, which can effectively promote the synthesis of vitamin D and strengthen the absorption of calcium. Parents should also pay attention to the fact that calcium supplementation for children should be moderate, not blindly excessive, and needs to be carried out under the guidance of a doctor, not self-medication.