Background: Physalis is the herb of the family Solananceae and has 100 species of one Physalis angulata L. Commonly known in Indonesia as ceplukan or ciplukan. Physalis angulata L. Contains active compounds that include flavonoids, polyphenols, Physalin B and chlorogenikacid as antibiotic. Streptococcus mutans produces acid compounds that can cause demineralized teeth so that the strength of teeth is reduced and can be problematic in the future Objective: To determine the effect of antibacterial activity of ethanol extract of the leaves ciplukan (Physalis angulata L.) against Streptococcus mutans Design: Experimental laboratory. Using ethanol extract of the leaves ciplukan (Physalis angulata L.) with a concentration of 100%, 50%, 25%, 12.5%, 6:25%,% 3:13, 1:56%, 0.78%, 12:39% and 0.2%. test bacteria used were Streptococcus mutans diluted with BHI liquid medium so that the concentration becomes 106CFU /ml. The reading of the results by measuring the MIC and MBC Result: The results showed the minimum inhibitory concentration (MIC) at a concentration of 0.78% and a minimum baktercidal concentration (MBC) at a concentration of 1,56%. Conclusion: The ethanol extract of leaves ciplukan (Physalis angulata L.) has the ability antibacterial power against Streptococcus mutans with MIC concentration of 0.78% and MBC concentrations of 1.56%.