After the treatment of periodontitis is completed, it is recommended to eat it half an hour later. This is because local medication needs a process of absorption and action, so it is recommended to drink water and eat after half an hour, so as to maximize the local effect of the drug. Periodontitis treatment includes several steps, including basic treatment, periodontal surgery, orthodontic treatment and curative effect review. The treatment of periodontitis includes supragingival scaling, subgingival scaling and regular review. After supragingival scaling and subgingival scaling, the doctor will clean some or all of the parts with serious gingival inflammation, and then apply drugs locally. After taking the medicine, the effect can reduce the inflammation of gums to a greater extent. There is a process of taking medicine and absorption, and local care should be carried out according to the doctor's advice.