Rough breathing sounds in infants may be associated with physiologic and pathologic causes such as pneumonia and allergic rhinitis. 1. Physiological reasons: It may be due to incorrect sleeping position or objects covering the mouth and nose, etc., which causes the baby’s breathing to be more laborious, and the baby may show a heavy breathing sound. 2. Pathological causes (1) Pneumonia: Lung infections caused by pathogens such as viruses or bacteria also cause airway inflammation. The mucous membrane of the airway of infants is prone to swelling and increased secretion, which cause the airflow to be unobstructed and lead to the coarsening of breath sounds. (2) Allergic rhinitis: Infants with allergic rhinitis may suffer from allergenic stimulation, which may lead to poor nasal ventilation, nasal congestion and other symptoms, resulting in heavy breathing. There may be other reasons for heavy breathing in infants, so it is recommended to consult a doctor for further examination, to clarify the cause with the help of the doctor, and to carry out targeted treatment or therapy.