Mouth ulcer (Recurrent Aphthous Stomatitis) is one of the most common diseases in the community. This disease can be caused by various factors, one of them is bacterium Streptococcus sanguis. Previous study showed that pomegranate peel extract (Punica granatum L.) had antibacterial activity regarding to the content of tannin. This study aims to know optimal concentration pomegranate peel ethanolic extract (Punica granatum L.) as antibacteria. Test to determine the optimal concentration extract in the inhibition of Streptococcus sanguis is prepared by agar diffusion method. The concentration of the extract were used 1%, 2.5%, 5%, 10% and 20%. Positive control used is albotyl, while the negative control used is aquadest. Patch formulation is prepared by solvent-casting method by varying the composition of chitosan, PVP and HPMC 1:2:2, 1:2:3 and 2:3:6. Antibacterial activity of patch is also prepared by agar diffusion method. Negative control used is formula of patch without extract. Statistical analysis is performed with Kruscal-Wallis method. The results shows that the optimal concentration of extract as antibacteria activity is 10%. Statistical analysis produces Kruscal-Wallis p-value which equal to 0.014. The post-hoc Mann-Whitney test shows that all of the extract concentration have a significant difference in inhibition to extract with a concentration of 1%. Meanwhile, pomegranate peel ethanolic extract (Punica granatum L.) can be formulated into patch dosage form with the the most satisfied characteristics found in the formula containing in the ratio chitosan, PVP and HPMC 1:2:3 and extract 5%. Pomegranate peel ethanolic extract (Punica granatum L.) patch shows no inhibition of the growth of the Streptococcus sanguis, which is considered releasing of active substance. However, pomegranate peel ethanolic extract (Punica granatum L.) has higher potency as antibacterial agent than the other controls.