Pustules inside the mouth may be related to chronic apical periodontitis, periodontitis, wisdom tooth pericoronitis, gum abscess, cyst and other causes, which need to be treated locally according to the cause. In addition, you can also apply antibiotics and other drugs under the guidance of the doctor for systemic treatment. 1. Chronic periapical inflammation: the root of the tooth is inflamed, and the exudate in the root cannot be discharged through the root canal and pulp cavity, but only through the gingival fistula or sinus tract, which leads to pus inside the mouth. After a clear diagnosis, root canal treatment is needed to clean the root canal, anti-inflammatory fistulae and sinus tracts after grinding the tooth open. 2. Periodontitis: abscess formation in the periodontal pockets, may also be manifested as long pus inside the mouth, which can be scaling, periodontal scraping, periodontal pockets, such as medication and other treatments, for the loosening of the serious teeth may have to be extracted. 3. Cysts: If the jawbone cysts secondary infection, may also be manifested as long pus inside the mouth, repeated pus overflow, through the X-ray or CT examination, the feasibility of surgery combined with anti-infection treatment. The application of systemic antibiotics can be carried out under the guidance of the doctor, including anti-anaerobic antibiotics, such as metronidazole, ornidazole and other drugs, as well as broad-spectrum antibiotics, such as cefixime and other drugs for the treatment of the use of drugs to comply with the doctor’s instructions.