A Randomized Clinical Trial Evaluating Antimicrobial Effectiveness of a New Licorice Oral Gel against Salivary Streptococcus mutans

INTRODUCTION: Dental caries is one of the most common health concerns, and the adverse effects of Chlorhexidine have increased the search for safer natural alternatives. This study aimed to compare the antimicrobial effect of a novel 1% Licorice root extract gel with 0.2% Chlorhexidine mouthwash in reducing salivary Streptococcus mutans (S. mutans). METHODS: In this randomized controlled trial, 30 adults with DMFT >2 were randomly divided into two groups to receive 0.2% Chlorhexidine mouthwash (n=15) or 1% Licorice gel (n=15) for seven days. Samples of unstimulated saliva were collected at the beginning and after the intervention. S. mutans colony-forming units per milliliter (CFU/mL) were determined and data were analyzed using SPSS v25.0. RESULTS: Both groups showed significant decreases in S. mutans counts after the intervention (P < 0.001). This reduction in the Chlorhexidine and Licorice gel group was 32.9% and 20.2%, respectively. However, there was no statistically significant difference between the two groups (P = 0.39). DISCUSSION: The 1% Licorice gel showed antimicrobial activity comparable to 0.2% Chlorhexidine, with a more favorable taste and no side effects. These findings support its potential as a tolerable herbal alternative for short-term oral care, especially in individuals intolerant to Chlorhexidine. CONCLUSION: Licorice gel appears to be a safe and effective natural agent for reducing salivary S. mutans levels. Further long-term studies with larger populations are necessary to verify its clinical applicability and sustainable efficacy.