Objectives: To assess and compare the antibacterial efficacy of 4% Tulsi, commercially available fluoridated (Colgate total care) and placebo dentifrices on salivary Streptococcus mutans counts among 14-15-year-old school children in Davangere city. Materials and methods: A triple blinded randomised controlled trial with a study population of 14-15-year-old school children. A sample of 84 participants was randomly selected and 2 ml of unstimulated saliva was collected. Microorganisms were cultured using Mitis Salivarius selective media. The participants with a 10⁵ colony-forming units (CFU) were considered as eligible. Block randomisation and concealed randomisation methods were adopted to allocate the participants into three groups containing 28 each. After seven days, a post assessment of salivary Streptococcus mutans count was done. Wilcoxon signed rank test for within group comparison and Kruskal Wallis ANOVA for intergroup comparison were used. Results: The study showed a significant reduction in salivary Streptococcus mutans counts from baseline to post-test (mean rank 37.95 - 25.27) in the Tulsi dentifrice group. The intergroup comparison showed a statistically significant difference (p=0.044). Post hoc analysis showed a statistically significant difference between the Tulsi and placebo dentifrice groups (p=0.026). Conclusion: 4% Tulsi extract incorporated in the form of dentifrice have shown a maximum reduction in the salivary Streptococcus mutans count, for a period of seven days when compared to fluoridated dentifrice. Keywords: Dentifrice, Tulsi, streptococcus mutans, dental caries, randomization