Newborn babies drink milk with throat like phlegm, which can be seen from the fact that the mucous membrane of the respiratory tract is not fully developed and mature after birth. Due to nutritional imbalance in the body, such as a relative lack of calcium, causing the laryngeal cartilage to be underdeveloped and the passage in the throat to be narrowed relative to normal, thus causing poor ventilation, the above symptoms can occur. At this time, you can check the level of bone density and the composition of active vitamin D in the blood, and if necessary, trace elements around 6 months of age of the baby. At more than 2 weeks of life, the baby can start feeding cod liver oil appropriately, and if the calcium deficiency is relatively obvious, calcium supplements should be taken, and the feeding regimen should be reviewed and adjusted at any time.