ABSTRAK Pendahuluan: Tingginya prevalensi karies gigi di Indonesia dapat dibuktikan dengan indeks DMF-T di Indonesia 2018 sebesar 7,1. Antibakteri yang dapat digunakan untuk mencegah kondisi tersebut adalah klorheksidin. Namun, klorheksidin memiliki efek samping. Sebagai alternatif digunakan tanaman herbal seperti daun Mangga gedong (Mangifera indica L) yang diduga memiliki efek antibakteri. Penelitian ini bertujuan untuk menganalisis konsentrasi hambat minimal (KHM) dan konsentrasi bunuh minimal (KBM) ekstrak etanol daun Mangifera indica L terhadap pertumbuhan Streptococcus mutans. Metode: Penelitian ini merupakan penelitian eksperimental dengan tujuh kelompok perlakuan, KHM diukur dengan metode mikrodilusi dengan variasi konsentrasi ekstrak (100 mg/ml; 75 mg/ml; 50 mg/ml; 25 mg/ml; 12,5 mg/ml; 6,25% mg/ml; 3,125 mg/ml ml). Klorheksidin 0,2% digunakan sebagai kontrol positif sebagai pembanding. KBM diukur dengan metode TPC dengan menggunakan colony counter. Analisis One Way Anova dengan Post Hoc Tukey digunakan untuk mengetahui perbedaan yang signifikan antara perlakuan. Hasil: Nilai KHM ekstrak daun Mangifera indica L pada konsentrasi 50 mg/ml dan nilai KBM adalah 100mg/ml. Ekstrak Mangifera indica L dengan konsentrasi tertinggi 100mg/mL dan klorheksidin memiliki nilai inhibisi dan viabilitas tertinggi terhadap pertumbuhan S. mutans, namun keduanya tidak berbeda secara signifikan sesuai dengan uji One Way Anova dengan Post Hoc Tukey (p=0,05). Simpulan: Kemampuan daya hambat yang ditunjukkan oleh ekstrak daun Mangifera indica L terhadap pertumbuhan bakteri S. mutans berbanding lurus dengan konsentrasi ekstrak, semakin tinggi konsentrasi ekstrak maka daya hambat yang dihasilkan semakin tinggi.Kata kunciantibakteri, chlorhexidine, ekstrak daun, mangga gedong, streptococcus mutansAntibacterial activity of gedong manggo leeaves Mangifera indica extract against Streptococcus mutans : eksperimental studyABSTRACTIntroduction: The high prevalence of dental caries in Indonesia is evidenced by the DMF-T index data for Indonesia 2018, which stands at 7.1. One common antibacterial medication used to treat this disease is chlorhexidine; however, chlorhexidine is associated with side effects. In search of an alternative, herbal plants are being explored, such as Mangifera indica L (Mango), which is believed to possess antibacterial properties. This study aims to investigate the minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of a 70% ethanol extract obtained from mango leaves against the growth of Streptococcus mutans. Methods: This study is designed as an experimental research involving seven distinct treatment groups. The minimal inhibitory concentration (MIC) was determined using the microdilution method, utilizing a range of extract concentrations: 100 mg/ml, 75 mg/ml, 50 mg/ml, 25 mg/ml, 12.5 mg/ml, 6.25 mg/ml, and 3.125 mg/ml. Chlorhexidine 0.2% was used as a comparative benchmark as the positive control. To assess the minimum bactericidal concentration (MBC), the Total Plate Count (TPC) method was employed, and colony counting was performed. A One-Way ANOVA analysis with Post Hoc Tukey's test was applied to assess significant differences between treatments. Result: The MIC value for the extract of mango gedong leaves was determined to be 50 mg/ml. On the other hand, the MBC value for the gedong mango leaf extract was found to be 100 mg/ml. When comparing the highest concentration of Gedong Mango extract (100 mg/mL) with chlorhexidine, it was observed that both exhibited the highest inhibition and viability values against S. mutans growth. However, according to the One-Way ANOVA test with Post Hoc Tukey analysis (p=0.05), there was no significant difference between the two treatments. Conclusion: The inhibition level demonstrated by the Gedong Mango Leaf extract against the growth of S. mutans bacteria is directly proportional to the concentration level. In other words, as the extract's concentration increases, the inhibition level also increases.Keywords antibacterial, extract, mango gedong leaves, klorheksidin, Streptococcus mutans