Piper betle leaves known as Sireh or Paan have been used as it is rich in antioxidant and antimicrobial properties. Meanwhile for Cinnamomum zeylanicum or known as cinnamon, it is commonly used in a sweet and savoury food to enhance the taste. Cinnamomum zeylanicum possesses various antifungal and antimicrobial activities. Due to lack of scientific prove on both plant species, this study was carried out to screen these plants and prove it antimicrobial property based on appearance of inhibition zone. In this research, the antimicrobial activity of ethanol and distilled water extract of Piper belle leaves and Cinnamomum zeylanicum was evaluated against bacteria found in human which are Escherichia coli also known as E. coli and mouth bacteria. To test on antimicrobial activities of plant species, paper disc diffusion and streak plate method was used. Cinnamomum zeylanicum show inhibition zone on both bacteria plates while Piper belle show no inhibition zone on mouth bacteria plate. This lead to assumption of Cinnamomum zeylanicum is the most efficient plant against bacteria than Piper belle. Meanwhile, the most optimum concentration is 100% of Cinnamomum zeylanicum extract as it show inhibition zone on both bacteria plates. This research aim to provide scientific proves and provide summary on the potential medicinal benefit of both plant which are Cinnamomum zeylanicum and Piper belle. The results indicate that traditional claims of effectiveness using herbs against certain bacteria lead to fruitful results if scientific studies were carried out to validate the traditional assumption.