Three-month-old babies with bronchopneumonia can usually get better in about 7 to 10 days, and healing may take a few weeks, while severe pneumonia and special pathogen infections tend to have a longer course of treatment and may even be life-threatening. The exact time will depend on your baby’s physical condition and the severity of the pneumonia. Some babies are mildly ill and may only have a cough, sputum and nasal congestion. The milder pneumonia, which needs to be differentiated according to the pathogen, can usually be effectively relieved in 7-10 days. However, specific pathogens such as adenovirus pneumonia may have a longer duration of symptoms, which can last for about 4 weeks. And whooping cough pneumonia can cough for as long as 12 weeks after entering the spasmodic cough phase. In addition, severe pneumonia is often treated differently from common pneumonia, and cannot be generalized. Treatment may require ventilator-assisted ventilation, intravenous glucocorticoids, and other symptomatic supportive therapy. The treatment process may require ventilator-assisted ventilation, intravenous glucocorticosteroids and other symptomatic supportive therapy. Therefore, the duration of treatment cannot be generalized. Usually, the baby will gradually improve in about 2-4 weeks. If your baby has pneumonia, it is recommended to consult a doctor for timely treatment and standardized medication under the doctor’s guidance.