Halitosis in students may be caused by diet, or oral diseases, nasopharyngeal diseases, etc. Generally, it is necessary to clarify the cause of the disease and treat the symptoms, and the treatment methods used for different diseases are different. 1. Diet: if you eat onions, garlic, leeks and other stimulating taste of food, may cause bad breath, generally do not need treatment, gargle or brush your teeth after meals, bad breath can be gradually relieved. 2. Oral diseases: such as dental caries, oral ulcers and other diseases, or due to periodontal disease, these may appear bad breath. Generally to treat the primary disease, such as dental caries, you can apply dental fillings, periodontitis should be periodontal basic treatment, oral ulcers can use mouthwash or watermelon cream and other drugs. After treatment of the above diseases, bad breath can generally disappear. 3. nasopharyngeal diseases: such as chronic pharyngitis, chronic sinusitis, etc., these diseases may have secretion exudation, there will be bad breath, it is recommended that a clear examination, follow the doctor’s instructions for symptomatic treatment, chronic pharyngitis is generally used pharyngitis tablets, iodine, etc., chronic sinusitis can be used to use roxithromycin and so on. It should be noted that the drugs need to follow the doctor’s instructions for medication, in addition to the treatment of disease at the same time, usually pay attention to oral hygiene, morning and evening adherence to brushing, rinsing the mouth after meals.