Swallowing saliva and feeling that one side of the ear is blocked may be caused by eustachian tube infection, secretory otitis media and other reasons. 1. Eustachian tube infection: when bacteria, viruses and other infections of the eustachian tube, it will cause edema of the mucous membrane of the eustachian tube, resulting in blockage of the eustachian tube, and the feeling that one ear is blocked when swallowing saliva. 2. Secretory otitis media: It is a kind of non-purulent disease of the middle ear mainly characterized by the accumulation of mucus or fluid in the middle ear, mainly related to the blockage of the Eustachian tube and the dysfunction of the Eustachian tube, etc. When the patient swallows saliva, he/she can feel that one side of the ear is blocked. When patients feel blocked on one side of the ear when swallowing saliva, there are other possibilities, and it is recommended to go to the hospital in time for examination and diagnosis, and choose the corresponding treatment under the guidance of the doctor.