The common causes of nasal congestion in infants at night are acute rhinitis, allergic rhinitis, sinusitis and so on. 1. Acute rhinitis: commonly caused by colds and nasal mucosal congestion, edema, the baby’s own nasal cavity is small, and the night position factors, easy to appear at night nasal congestion discomfort, improve the position can be relieved. 2. Allergic rhinitis: there can be nasal congestion at night, due to the slow blood flow at night, parasympathetic nerve excitation, vascular congestion in the nose, resulting in nasal turbinate hypertrophy and nasal congestion. 3. Sinusitis: for infants during the daytime activities or standing position for a long time is conducive to nasal discharge, when the night lying down to maintain a resting state, nasal secretions are easy to retain the discomfort caused by nasal congestion. In short, when there is nasal congestion discomfort, we recommend timely medical treatment to identify the cause of the disease, targeted treatment.