Nose can not smell the taste, clinically common causes are rhinitis – sinusitis, nasal cavity hyperplasia tissue, some of the elderly degenerative diseases. 1. Rhinitis – sinusitis: rhinitis – sinusitis caused by nasal congestion, is the most common cause of reduced sense of smell, external gases can not reach the location of the olfactory cleft, the sense of smell appeared to weaken the situation. 2. Nasal hyperplasia: some people suffer from intranasal polyps or nasal tumors, which may block the olfactory fissure area, thus causing the body to have a reduced sense of smell. 3. Degenerative diseases in the elderly: the mucous membrane in the nasal cavity of some elderly people is prone to dryness, and the local dryness may also cause the sense of smell to be reduced or loss of smell. The sense of smell is one of the important functions of the nasal cavity, when the body has symptoms of reduced sense of smell, it is recommended to go to the hospital to clarify the cause of the disease and standardize the treatment.