<![CDATA[Staphylococcus aureus is a pathogenic bacterium that causes skin infections and can be transmitted via the hands; therefore, antiseptic soaps containing natural active ingredients are needed as alternatives to synthetic antibacterial agents. Kedoya leaves (Dysoxylum gaudichaudianum) contain flavonoids, alkaloids, tannins, and steroids with antibacterial potential, but their use in liquid soap formulations has not been widely studied. This laboratory experimental study aimed to formulate a hand antiseptic liquid soap containing ethanolic kedoya leaf extract at concentrations of 0.5%, 1%, and 2%, and to evaluate its physical quality and antibacterial activity against S. aureus, using a soap base without extract as the negative control and Dettol liquid soap as the positive control. Physical quality was assessed by organoleptic, foam height, and pH tests, while antibacterial activity was determined by the disc diffusion method and analyzed using one-way ANOVA followed by the LSD test. All formulas met the SNI 06-4085-1996 requirements (foam height 67–72 mm; pH 8.8–8.9). The inhibition zone increased with extract concentration: 15.3 mm (0.5%), 18.7 mm (1%), and 20.6 mm (2%), with significant differences among concentrations (p < 0.05). According to the Davis and Stout criteria, the 0.5% and 1% formulas showed strong inhibition, whereas the 2% formula showed very strong inhibition, although still lower than the positive control (25.2 mm). This study provides initial evidence that kedoya leaves, a local plant of Southeast Sulawesi, can be developed as a natural antibacterial active ingredient in hand antiseptic liquid soap, with the 2% formula being the most promising for further development.]]>
