Article Type: ---- Unspecified ----

Background : The antimicrobial properties of plant extracts have shown promise for development of new drugs. This study was conducted to measure the antibacterial activity of grape (Vitis vinifera) seed extract against Streptococcus mutans and Aggregatibacter actinomycetemcomitans.
Materials and Methods : In this experimental study the grape seed extract have been prepared with maceration method. The antimicrobial activity of the extract was examined by determining Minimum Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) using the macro dilution broth technique.
Results : MIC and MBC for Aggregatibacter actinomycetemcomitans was 3.84 mg/mL and 7.68 mg/mL respectively.There were not any inhibitory effects against Streptococcus mutans.
Conclusion : The Grape seed extract has inhibitory and bactericidal effects against Aggregatibacter actinomycetemcomitans. There were not any bactericidal or bacteriostatic effects against Streptococcus mutans.