Sudden loss of hearing in one ear is most often seen in patients with sudden deafness. The cause of sudden deafness is unknown, mostly related to vasospasm and viral infection, manifested as sudden hearing loss, which may be accompanied by tinnitus and vertigo, etc. On examination, there is no abnormality in the external auditory canal and tympanic membrane, and electrical audiometry suggests neurological deafness with an A-shaped curve of acoustic impedance. Treatment is given to patients with hormone therapy, such as dexamethasone drip, post- or intra-ear injection of dexamethasone, application of vasodilator drugs, such as betahistine hydrochloride, if accompanied by tinnitus, lidocaine hydrochloride can be added intravenously, and can also be supplemented with hyperbaric oxygen and other treatments. The treatment course of ten days is a course of treatment, most of the treatment effect is good, up to three courses of treatment, if the effect is not good after treatment, can wear hearing aids and other treatment.