Nostrils for a while the left side of the blockage for a while the right side of the blockage for a long time to consider chronic simple rhinitis, a short time to consider for the cold. 1. Chronic simple rhinitis: it is a chronic inflammation that occurs in the mucous membrane and submucous layer of the nasal cavity, and is generally reversible. Clinical manifestations are characterized by intermittent, alternating nasal congestion, increased nasal discharge is generally mucus white nasal discharge, longer time will also have a headache, decreased concentration and other clinical manifestations. 2. Colds: mostly due to viral or bacterial respiratory infections, the main reason for the onset of the disease is due to the body’s own immunity decline. Therefore, it should be treated in time. Pay attention to a light diet, drink as much water as possible to avoid exertion. If the symptoms cannot be relieved or worsen for more than three to five days, you need to go to the hospital for examination and treatment. Symptoms of alternating nasal congestion, please consult a doctor in time, do not use medication privately.