<![CDATA[Background: Staphylococcus aureus is an opportunistic pathogenic bacterium that causes skin and soft tissue infections, with a reported prevalence of 45.3% among skin and soft tissue infection cases in Indonesia. Rising antibiotic resistance has encouraged the development of alternative antibacterial agents from natural products. Legundi fruit (Vitex trifolia) contains secondary metabolites such as flavonoids, terpenoids, alkaloids, tannins, and saponins with antibacterial potential. Objective: To determine the antibacterial activity of ethanol extract of legundi fruit (Vitex trifolia) against Staphylococcus aureus growth by determining its Minimum Inhibitory Concentration (MIC). Methods: This true experimental study used a Pretest-Posttest with Control Group Design and the liquid dilution method with extract concentrations of 50%, 25%, 12.5%, 6.25%, 3.125%, 1.56%, 0.78%, and 0.39%, along with positive and negative controls. MIC was determined by measuring absorbance values before and after 24-hour incubation using a UV-Vis spectrophotometer at 600 nm. Results: A decrease in optical density (ΔOD ≤ 0) was observed at concentrations of 50%, 25%, and 12.5%, indicating inhibition of Staphylococcus aureus growth, while an increase in absorbance occurred at lower concentrations. The last concentration showing a decrease in ΔOD was 12.5%. Conclusion: The Minimum Inhibitory Concentration (MIC) of ethanol extract of legundi fruit (Vitex trifolia) against Staphylococcus aureus was determined to be 12.5%.]]>
