Background: Amongst the specific plaque pathogen Aggregatibacter actinomycetemcomitans (Aa) ATCC 43718 serotype b is one of the highly virulent bacteria that causes periodontitis. Probiotic therapy is a treatment in which the lactic acid bacteria in are utilized to impede the colonization and growth of the pathogenic bacteria to prevent the further formation of dental plaque. Objective: The present research aimed to evaluate inhibiting effect of purified bacteria from various commercially available yogurt product containing bacteria named (Lactobacillus casei strain Shirota; Lactobacillus bulgaricus and Streptococcus thermophilus; Lactobacillus reuteri Prodentis) on the growth of Aa. Methods: The research made use of the diffusion method by fixing Aa on BHIB (brain heart infusion broth) medium, incubated at 37 °C and 24 hours later planted on MHA (Mueller-Hinton agar) media. Aa were divided into four subgroups each with a paper disk; group 1 consists of untreated bacteria (i.e., control group), group 2 with purified bacteria from Yakult 0.5 \muL, group 3 with purified bacteria from Cimory Yogurt Drink 0.5 \muL and group 4 with purified bacteria from BioGaia Prodentis 0.5 \muL. All commercially available yogurt were treated to get the purified probiotic. Additionally, it was incubated for 24 hours at 37 °C and later the inhibition zone diameter was observed. Results: In the research, it was found that the average impeding ability, so-called inhibition zone, in group 1 indicated 0 mm, group 2 indicated 12.70 mm, group 3 indicated 16.60 mm and group 4 indicated 19.60 mm. The statistical test outcomes showed a significance of 0.000 (p 0.05). Conclusions: The purified bacteria from three probiotics indeed inhibit the growth of the Aa bacteria and a substantial difference in the diameter of the inhibition zone were found among the three probiotics.