There are a large number of bacteria in the mouth, forming a vast flora, and these bacteria are prone to cause certain damage to the oral cavity. Routinely, there are cariogenic microorganisms, such as Streptococcus spp, Lactobacillus spp, Actinobacillus spp, and the main most common one is Streptococcus pyogenes, and Streptococcus pyogenes is easy to cause caries. Usually Lactobacillus is also prone to cause sulcus caries, and Actinobacillus is prone to cause root surface caries in teeth, and this condition usually also needs to cooperate with the metabolism of sugar. If there is periodontal disease, there may also have Porphyromonas gingivalis, Prevotella intermedia, etc., so that are easy to produce periodontal disease, so many bacteria in the oral cavity are easy to produce to cause harm to the oral cavity, then we should control the flora in the mouth, and often use mouthwash to inhibit the development of flora in the mouth, such as compound chlorhexidine rinse.