Gingivitis is primarily caused by the presence of dental plaque on the gums, which is erosive due to the large amount of bacteria. Taking oral amoxicillin, an antimicrobial drug, does not show a very obvious effect. One reason is that the gum tissue is relatively tough, and the concentration of the drug in the gum tissue when administered systemically is not sufficient to provide the expected therapeutic effect. Another reason is that oral bacteria, mostly anaerobic bacteria, cause this condition, and general anti-inflammatory drugs do not work well. The best method to treat gingivitis is still dental cleaning, which can directly remove the bacteria on the gums, clearly affecting the treatment. Subgingival scaling is also effective, which can lead to better outcomes.