B ackground: Periodontal disease is a disease of the teeth and mouth that is often found in Indonesia. Periodontal disease caused by microorganisms that occur in the supporting tissues of the teeth. Treponema denticola and Porphyromonas gingivalis are bacteria that play an important role in the pathogenesis of periodontal disease. Mechanical treatments such as scaling and brushing, as well as chemical treatments such as gargling with chlorhexidine which has antimicrobial properties can inhibit the growth of periodontal bacteria. Alternative therapy can be done by using herbal medicines that are being studied, one of which is pineapple hump (Ananas comosus) which can inhibit the bacteria that cause periodontal disease. Objective: To determine the effect of pineapple hump extract (Ananas comosus) on bacterial growth and adhesion of the biofilm Treponema denticola, and Porphyromonas gingivalis. Method: The bacterial inhibition test was carried out using the agar well diffusion method and the biofilm density measurement using the biofilm assay method. Result: Pineapple hump extract can inhibit bacterial growth optimally at a concentration of 100% with an average diameter of 10 mm for Treponema denticola and 7.3 mm for Porphyromonas gingivalis. And it can eradicate the adhesion of Treponema denticola biofilm optimally at a concentration of 100% in a 24-hour incubation with an average optical density of 0.064 and a concentration of 50% in a 6-hour incubation with an average OD 0.124 against Porphyromonas gingivalis. The normality test using the Shapiro-Wilk method showed that the data were normally distributed (p> 0.05). One-way ANOVA test and Post Hoc test showed that there was a significant difference (p <0.05) between the ability of pineapple hump extract and between concentrations in inhibiting bacteria and biofilms Treponema denticola and Porphyromonas gingivalis. Conclusion: Pineapple hump extract can inhibit bacterial growth and eradicate the adhesion of Treponema denticola and Porphyromonas gingivalis biofilms.