<![CDATA[Kenikir leaf (Cosmos caudatus Kunth.) contains secondary metabolites such as flavonoids, saponins, tannins, and alkaloids that have potential as natural antibacterial agents. This study aimed to formulate the ethyl acetate fraction of kenikir leaf into a liquid soap preparation, evaluate its physical quality over 4 weeks of storage, and analyze its antibacterial effectiveness against Staphylococcus aureus. Extraction was performed by maceration using 96% ethanol, followed by liquid-liquid fractionation (LLF) using ethyl acetate. The liquid soap was formulated at four fraction concentrations: F0 (0%), F1 (2.5%), F2 (5%), and F3 (7.5%). Evaluation included organoleptic, homogeneity, pH, foam height, and viscosity tests. Antibacterial activity was assessed using the well diffusion method, followed by Welch ANOVA and the Games-Howell post-hoc test. The results showed that all formulas (F0-F3) met physical quality standards, remained stable and homogeneous during storage, and had pH values of 8.75-9.61, foam heights of 77.6-91.2 mm, and average viscosities of 1,435-1,565 cP. The average inhibition zones were 4.49 mm (weak) for F0, 6.17 mm (moderate) for F1, 9.16 mm (moderate) for F2, 11.49 mm (strong) for F3, and 21.44 mm (very strong) for the positive control (Dettol). Welch ANOVA showed a significant difference between treatment groups (p<0.001). It can be concluded that the ethyl acetate fraction of kenikir leaf can be formulated into stable liquid soap, with F3 (7.5%) showing the strongest antibacterial potential against Staphylococcus aureus as a topical preparation.]]>
