<![CDATA[Abstract: Binjai is one of the typical plants of South Kalimantan, which contains saponins and tannins. The aim of this study was to analyze the differences in inhibitory activity of binjai root extract against Escherichia coli and Pseudomonas aeruginosa in vitro. The research design uses true experimental; post test-only with control group design consisting of 10 treatments (50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%) and positive control (siprofloxacin 5µg). Data from this study were analyzed using one-way ANOVA test, post-hoc Duncan test, and independent t test at 95% confidence level. The results showed that there were significant differences in inhibition of all treatments and there was an increase in inhibitory effect according to increased concentration. The optimum binjai root extract inhibited at a concentration of 90% against Escherichia coli (25.13 mm) and at a concentration of 85% against Pseudomonas aeruginosa (16.99 mm). Binjai root extract has greater inhibitory activity against Escherichia coli than Pseudomonas aeruginosa at the same concentration. Conclusions, there are differences in inhibitory activity of binjai root extract against Escherichia coli and Pseudomonas aeruginosa. Keywords: binjai root extract, inhibitory activity, Escherichia coli, Pseudomonas aeruginosa Abstrak: Binjai merupakan salah satu tumbuhan khas Kalimantan Selatan, yang mengandung saponin dan tanin. Tujuan penelitian ini yaitu menganalisis perbedaan aktivitas daya hambat ekstrak akar binjai terhadap Escherichia coli dan Pseudomonas aeruginosa in vitro. Rancangan penelitian menggunakan true experimental; post test-only with control group design yang terdiri dari 10 perlakuan (50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%) dan kontrol positif (siprofloksasin 5µg). Data hasil penelitian dianalisis menggunakan uji one-way ANOVA, uji post-hoc Duncan, dan uji t independent pada tingkat kepercayaan 95%. Hasil penelitian didapatkan perbedaan aktivitas daya hambat yang bermakna dari semua perlakuan dan terdapat peningkatan daya hambat sesuai dengan peningkatan konsentrasi. Ekstrak akar binjai menghambat secara optimum pada konsentrasi 90% terhadap Escherichia coli (25,13 mm) dan konsentrasi 85% terhadap Pseudomonas aeruginosa (16,99 mm). Aktivitas daya hambat ekstrak akar binjai lebih besar terhadap Escherichia coli dibandingkan Pseudomonas aeruginosa pada konsentrasi yang sama. Simpulan, terdapat perbedaan aktivitas daya hambat ekstrak akar binjai terhadap Escherichia coli dan Pseudomonas aeruginosa. Kata kunci: ekstrak akar binjai, daya hambat, Escherichia coli, Pseudomonas aeruginosa]]>
