Background and Objectives: The aim of this study was to evaluate the effects of probiotic Bacillus clausii UBBC-07 2 Billion spores alone and in combination with scaling in a randomized, placebo-controlled clinical trial of volunteers with chronic generalized gingivitis. Materials and Methods: Thirty otherwise systemically healthy, chronic generalized gingivitis subjects (both males and females, aged between 18 and 40 years) were included. Selected subjects were randomly divided into two groups. The study period was 7 days. “Split-mouth” design was used for scaling, which was performed on day 0; two quadrants (either right or left) were treated with scaling whereas the remaining two quadrants were left untreated. Participants in the test group received probiotics, B. clausii UBB-07-2 Billion spores as mouth rinse twice daily for 7 days and in the control group received placebo rinse twice daily for 7 days. Further treatment for the subjects was carried out after 7 days. Statistical analysis was done for comparisons of clinical parameters (plaque index [PI], gingival index [GI], and sulcus bleeding index [SBI]). A P Results: At day 7, the PI, GI, and SBI were significantly reduced by all treatment modalities. When ranked, the amount of PI, GI, and SBI reduction by the different treatments were scaling with probiotics, probiotics, scaling with placebo, placebo all differences were statistically significant. Conclusion: The present randomized double-blind controlled trial confirms the plaque inhibition effects of B. clausii UBB-07-2 Billion spores probiotics. B. clausii UBB-07-2 Billion spores probiotic can be recommended alone and in combination with scaling and also during the maintenance phase of periodontal treatment.