The inability to hear in the left ear may be related to cerumen impaction, acute otitis media, traumatic tympanic membrane perforation, etc. Different diseases need to be treated, including general treatment, medication and surgery. 1. For cerumen impaction, use sodium bicarbonate ear drops as prescribed by the doctor, which can soften the cerumen and help to remove it. 2. For acute otitis media, glucocorticoids such as dexamethasone and prednisone can be used as prescribed by the doctor, and oral penicillin and other antibiotics can be used to fight infection, which can help to relieve the symptoms. 3. For trauma caused by tympanic membrane perforation, it should be strictly prohibited to flush the ear canal, part of the hearing impairment is serious, according to the specific circumstances of the choice of tympanic membrane patch, tympanoplasty and other surgical methods to repair the tympanic membrane. It is recommended that people who can not hear in the left ear consult a doctor in time to clarify the cause of the disease, under the guidance of the doctor to standardize the use of medication and treatment.