Objective:To evaluate the effect of periodontal therapy and local application of Kouling(gargle of composite of phenols in tea)on the subgingival bacteria and levels of endotoxin in gingival crevicular fluid of adult periodontitis.Methods:Seventy-eight adult periodontitis(156teeth)were divided into three groups randomly.The experimental group was treated with periodontal scaling and root planning

and meanwhile administered gargle of composite of phenols in tea.The negative control group was treated with periodontal scaling and root planning

and administered distilled water as placebo.And the positive control group was treated with periodontal scaling and root planning

and administered0.2%chlorhexidine. Levels of endotoxin in gingival crevicular fluid were measured and the subgingival bacteria were cultivated before and after therapy.Results:After therapy

levels of endotoxin in gingival crevicular fluid and numbers of bacteria all decreased remarkably in three groups(P<0.05).Level of endotoxin in gingival crevicular fluid of experimental group after therapy was significantly lower than that of negative control group(P<0.05). The number and composition of subgingival bacteria changed significantly

and bacterial total number and levels of gram-negative bacteria of experimental group decreased significantly after therapy comparing with negative control group(P<0.05)

and levels of gram-positive bacteria increased(P<0.05).Conclusion:Periodontal scaling and root planning combining local application of gargle of composite of phenols in tea had apparent effect on the subgingival bacteria and levels of endotoxin in gingival crevicular fluid of adult periodontitis.