Aim: To evaluate the antimicrobial efficacy of liquorice extract on common oral pathogenic microorganisms like Streptococcus mutans, Staphylococcus aureus, Lactobacillus and Enterococcus faecalis. Materials & Methods: Liquorice root was dried, pulverised and refluxed with ethanol using reflux condenser. The crude extract was filtered using a whatmann filter paper. The antimicrobial efficacy was evaluated by agar well diffusion method and the minimal inhibitory concentration was determined using serial dilution test. Results: Zones of inhibition were measured as 17 mm in S.mutans, 30mm in S.aureus, 35 mm in Lactobacillus & 25 mm in E.faecalis. The lowest concentration of liquorice test solution that inhibited microbial growth on culture plates was considered as minimum inhibitory concentration - 75%. Conclusion: Within limitations of this study, it can be concluded that liquorice extract showed antibacterial activity against S.mutans, S.aureus, Lactobacillus & E.faecalis
