<![CDATA[Typhoid fever is an infectious disease caused by Salmonella typhi bacteria with a high mortality rate in Indonesia. Inappropriate use of antibiotics can lead to bacterial resistance, so safer natural antibacterial alternatives are needed. Avocado leaves (Persea americana) and papaya leaves (Carica papaya) are known to contain secondary metabolite compounds such as flavonoids, alkaloids, saponins, and tannins that have antibacterial potential. This study aims to test the effectiveness of a combination of avocado and papaya leaf extracts on the inhibition of Salmonella typhi in vitro. This study was a laboratory experimental study with a completely randomized design (CRD) using the Kirby-Bauer disc diffusion method. The extract was prepared by maceration using 96% ethanol. The treatments consisted of a positive control of 0.005% chloramphenicol, a negative control of sterile distilled water, single extracts of avocado and papaya leaves at concentrations of 25, 50% 75, and 100%, and a combination of extracts at a ratio of 1:1, 2:1, and 1:2, each treatment was repeated three times. Data were analyzed using the Kruskal–Wallis test followed by the Mann–Whitney test. The results showed that all treatments were able to inhibit the growth of Salmonella typhi with a moderate inhibitory effect. A single papaya leaf extract had a higher inhibitory effect than avocado leaf extract and several extract combinations. The highest inhibitory effect was obtained from papaya leaf extract at a concentration of 50% with an average inhibition zone diameter of 9.49 mm. Antibacterial activity is influenced by bioactive compounds that work to damage the membrane and cell walls of bacteria. Based on the results of the study, it can be concluded that the combination of avocado leaf and papaya leaf extracts showed an additive antibacterial effect, while a single papaya leaf extract was more effective in inhibiting the growth of Salmonella typhi than the combination of the two extracts.]]>
