Mouthwash has a certain effect on bad breath, but the effect can not be maintained for a long time, because the mouthwash contains antiseptic drugs, it is not recommended to use for a long time. If you use it for a long time, it may cause staining on the tongue and the flora in the mouth may change. The real treatment for bad breath is periodontal therapy, because 80% of bad breath is caused by chronic periodontitis, which leads to red, swollen, bleeding and pus-filled gums, and then an unpleasant odor in the mouth. Through thorough periodontal treatment, plaque and calculus are cleaned up, and bad breath naturally disappears after the inflammation of the gums subsides. For bad breath caused by gastrointestinal and pulmonary diseases, treatment of the related diseases is also required.