Foul odor in the ear should be addressed differently depending on the cause. Common causes include inflammatory diseases of the outer ear as well as the middle ear, and in rare cases, tumor diseases. Common treatments include cleaning, medication, or surgery. 1. Otitis externa: If otitis externa is caused by cerumen impaction, water in the ear canal, or bad ear digging, the ear canal will be swollen and painful, and the ear will smell bad, etc. Antibiotic ear drops can be given or the ear canal can be cleaned with hydrogen peroxide. If there is cerumen embolism, it is necessary to thoroughly clean the cerumen mass under otoscopy. 2. Otitis media: Otitis media caused by suppurative bacterial infection, etc., will have earache, pus flowing from the ear canal, smelly ear canal, etc., and need to be treated with antibiotics or combined with glucocorticosteroid drugs, and need surgery if necessary. 3. External ear or middle ear tumor disease: clinical symptoms include ear canal pus, pain, bad smell, bloody secretion and so on. Combined with otoscopy, temporal bone CT and other examinations, comprehensive analysis is needed to make a clear diagnosis. Surgery or combined radiotherapy treatment is needed. Therefore, if there is a foul smell in the ear, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment.