1Department of Biology, Neyshabur Branch, Islamic Azad University, Neyshabur, I. R. Iran
2Department of Microbiology and virology, Mashhad University of Medical Sciences, Mashhad, I. R. Iran
3Department of Pharmacology, School of Medicine , Mashhad University of Medical Sciences , Mashhad , I.R. Iran
Objectives: Oral infections and dental caries are still considered as serious public health problems and inflict a costly burden to health care services around the world and especially in developing countries. Materials and Methods: In the present study, we evaluated the antibacterial activity of Glycyrrhiza glabra (G. glabra) against oral pathogens by diffusion methods and determined the minimum inhibitory concentration (MIC) by both broth and Agar dilution methods and minimum bactericidal concentration (MBC) by broth dilution methods. Results: In this study, G. glabra extract showed good antibacterial activity against six bacteria. No strain in this study showed resistance against this extract. Conclusion: G. glabrais suggested as an appropriate candidate to help us in order to control dental caries and endodontic infections.