Goal: To evaluate and contrast the antibacterial activity of mouthwashes containing 0.5% guava leaf extract and 0.1% turmeric extract on Streptococcus mutans counts in patients who are at high risk for dental cavities. Methods: This randomized clinical trial was conducted among 60 high-caries-risk patients (30 per group). Group A received 0.5% guava leaves extract mouthwash, while Group B received 0.1% turmeric extract mouthwash. Participants rinsed with 10 ml of mouthwash twice daily for 14 days. Saliva samples were collected at baseline and post-intervention to quantify S. mutans colonies using Mitis Salivarius Agar. Salivary pH was recorded, and patient satisfaction was assessed using a structured questionnaire. Results: The guava mouthwash group showed a significantly greater reduction in S. mutans counts (mean reduction: 2.1 × 10⁵ CFU/ml) compared to the turmeric group (mean reduction: 1.2 × 10⁵ CFU/ml) (p < 0.05). Salivary pH improved towards alkalinity in the guava group (from 6.4 to 7.0) compared to the turmeric group (from 6.5 to 6.8). Patient satisfaction scores were higher for guava (83.3% rated taste as pleasant) than turmeric (63.3%). Conclusion: Within the parameters of this study, 0.5% guava leaves extract mouthwash was more effective as an antibacterial agent against Streptococcus mutans than 0.1% turmeric extract mouthwash. It presents a promising natural alternative for managing dental caries risk.