Background:- Tea and coffee are the two most consumed drinks in the world after water. Green tea, Camellia sinensis (Theaceae) and Green coffee, Coffea arabica (Rubiaceae) possess antimicrobial activity in adjunct to various biological properties. Through this study, we have analysed the antimicrobial properties of Green tea and Green coffee extracts in contrast to chlorhexidine which was used as the control against Streptococcus mutans. Aim: To comparatively evaluate the antimicrobial potential of Green tea and Green coffee extract at various volumes against Streptococcus mutans. Methodology: Ethanolic extracts of Green tea and Green coffee were prepared. Streptococcus mutans were cultured on blood agar, which was then inoculated with these samples. Antimicrobial properties were determined using disc diffusion method at three different concentrations(10µL, 20µL, 30µL). The results were compared with 0.2% chlorhexidine solution(gold standard). Results:- Highest zone of inhibition was found with chlorhexidine (26.6 mm) at 30 µL followed by green tea (24.4 mm) and green coffee (17.7 mm) against streptococcus mutans. Results were statistically analysed with the analysis of variance (ANOVA). Conclusion: Green tea extracts(ethanolic) showed a greater inhibitory effect on the growth of Streptococcus mutans than green coffee.
