Do you know why the number of illnesses, the type of illnesses, and the severity of symptoms vary from age to age? Why do infants and toddlers get sick more often than older children and adults, and why are the symptoms more severe? This is determined by the physical characteristics of babies at different ages. From birth to 18 years old, the baby’s body is constantly growing and developing, so the function of the baby’s organs and resistance to disease are obviously different at different ages. Careful understanding of the physical characteristics of babies at different ages, especially the differences between the physical characteristics of infants and toddlers and those of older children and adults, is the most important first step for parents to care for their babies and prevent them from being harmed by diseases. Understanding the physical characteristics of the baby, in order to better care for the baby, prevention and control of disease. For example, infants and toddlers have narrow airways, immature bronchial and lung development, and weak cough reflexes, so when babies suffer from bronchitis and pneumonia, they often have difficulty breathing due to increased phlegm secretion blocking the airways, so for this feature, treatment and care should be given to the baby with phlegm medication, appropriate hydration for the baby, more turning and patting the baby’s back, etc., to help the baby drain the phlegm, and use strong cough suppressants for infants and toddlers is The use of strong cough suppressants for infants and toddlers is contraindicated. The baby’s blood antibody concentration is the lowest at 6 months after birth, and only at about 3 years of age does it approach the level of adults, so infants are susceptible to diseases because of this, plus infants have weaker organ functions than adults, which can easily lead to serious illnesses, so care needs to be taken with special care.