Buzzing in one ear may be caused by ear diseases, brain diseases, systemic diseases and so on. It is necessary to go to the hospital and undergo relevant examinations before further treatment. 1. Ear diseases, such as otitis externa, otitis media, ear trauma, cerumen impaction, can lead to buzzing in one ear, and in severe cases, deafness and dizziness may occur. 2. Brain diseases: such as encephalitis, meningitis, craniocerebral trauma and other diseases may cause stimulation and damage to the auditory nerve, which may lead to buzzing in one ear, and may also be accompanied by deafness and vertigo. 3. Systemic diseases: Buzzing in one ear may also be related to systemic diseases such as hypertension, stress, diabetes, etc. 4. Other causes: buzzing in one ear may be a precursor to certain diseases, such as tinnitus after streptomycin injection, tinnitus in hypertensive patients with rising blood pressure, and tinnitus may also be a precursor symptom of heart disease. One side of the ear buzzing, with or without other symptoms, it is recommended to go to the hospital as soon as possible to carry out the appropriate examination, to clarify the specific causes, to carry out professional treatment, to avoid delays in treatment.