Normal people also have alternating ventilation in the nose, but this alternating change is not subjectively perceptible, which is a change in the nasal cycle. If the patient has inflammatory and allergic diseases of the nasal cavity and sinuses, the symptoms of alternating nasal congestion will be obvious and can be felt subjectively. During the night sleep, the nasal congestion symptoms are further aggravated due to the side lying sleep position, which tends to appear towards the lower side. When turning over, there will be a significant nasal congestion symptom on the other side of the nose. If the patient has alternating ventilation symptoms for a longer period of time, a further detailed examination of the nose is required, followed by targeted treatment and management measures.