Alternating nasal congestion may be a normal physiologic manifestation or a pathologic manifestation caused by the action of infection, allergy, and other factors. Nasal congestion is a common symptom. In physiologic conditions, there is a nasal cycle in which the mucosal blood vessels of the bilateral turbinate show alternating systole and diastole, resulting in alternating changes in bilateral nasal resistance to facilitate turning over during sleep. The cycle is often not noticeable in normal subjects, but in those with bilateral nasal asymmetry, such as septal asymmetry, there may be significant cyclic nasal congestion. In addition, pathologic alternating left and right nostril nasal congestion is often caused by inflammatory or vascular-neurogenic factors of the nasal mucosa, such as bacterial and viral infections, allergic reactions, endocrine disorders, autonomic disorders, and the application of certain drugs. The effect of these factors makes the nasal mucosa congestion, secretion increase, vascular regulation malfunction, during sleep position change makes the mucosal blood, secretion redistribution by gravity, thus appear bilateral alternating nasal congestion. In summary, it is recommended to consult a doctor to standardize the diagnosis and treatment when necessary.