Background: Pre-procedural mouth rinsing has been shown to reduce pathogenic microorganisms, prevent secondary infections, and shorten healing time prior to periodontal treatment, oral surgeries, and endodontic procedures. In Mongo lia, most dental clinics routinely recommend mouth rinsing before treatment. Moreover, since the COVID-19 pandemic, there has been a notable increase in the public’s use of various mouth rinses outside clinical settings. However, there is a lack of comparative clinical studies assessing the efficacy of these commercially available rinses. Aim: To clinically compare the effects of various commonly used mouth rinses with different active ingredients on the oral environment. Materials and Methods: A case-control study was conducted involving 210 participants with mixed dentition, receiving care at the Pediatric and Preventive Dentistry Department of the Central Dental Hospital of Mongolian National Univer sity of Medical Sciences. Participants completed a 17-question survey in three groups, followed by clinical examinations. Oral pH, malodor, and bacterial counts were measured using a phase-contrast microscope (OMAX 40X-2500X, USA) after collecting plaque and saliva samples. Ethical approval was obtained from the Research Ethics Committee of the Mongolian National University of Medical Sciences. Data analysis was performed using STATA 14. Results: A total of 210 children participated (mean age 9.04±1.2 year; 52.2% male, 47.8% female). The average DMFT index was 6.3 DMF+df/t (high), and oral hygiene index was 1.53 score (moderate). The baseline oral pH was 6.3±0.5 score. After rinsing with sodium bicarbonate, the pH increased to 7.4±0.4 score, and remained at 6.61±0.31 score after 40 minutes. In contrast, the placebo group showed minimal change (6.06±0.45 to 6.09±0.31 score). Statistically significant differences between groups were observed. Baseline oral malodor averaged 80.8±1.4 ppb. After rinsing with povidone-iodine, it decreased to 76.1±3.4 ppb at 40 minutes, while in the placebo group it decreased from 74.2±4.9 ppb to 66.3±3.8 ppb. Bacterial count prior to rinsing was 18.85±0.77 score. Chlorhexidine gluconate reduced this to 11.06±0.68 score immediately after rinsing and to 8.8±3.8 score after 40 minutes, whereas the placebo group showed minimal reduction (15.21±2.02 to 17.6±2.2 score). Conclusions Pre-procedural mouth rinsing demonstrated a statistically significant positive impact on the oral environ ment, including improvements in breath odor and a reduction in microbial load. The effectiveness of these outcomes was found to vary depending on the specific composition of the mouthwash used. These findings suggest that selecting an appropriate mouthwash based on the clinical setting can enhance treatment efficiency. Nonetheless, all evaluated solutions contributed to maintaining or improving the balance of the oral environment.