Background: Aggressive periodontitis is a disease that rapidly destroys the periodontal tissue caused by the dominance of Aggregatibacter actinomycetemcomitans bacteria by 90%. Aggressive periodontitis treatment can be in the form of antibiotics. One of the antibiotics that can be used is metronidazole gel 25%, but this drug can have side effects if used in the long term. There are herbal plants, namely kecapi leaves (Sandoricum koetjape Merr) which contain compounds that can be used as antibacterials including saponins, alkaloids, flavonoids, and triterpenoids. Objective: To determine the antibacterial effectiveness of kecapi leaves extract (Sandoricum koetjape Merr) concentrations of 10%, 20%, 30%, 40%, 50%, 60%, and 70% on the growth of Aggregatibacter actinomycetemcomitans bacteria. Methods: True experimental design with post test only with control group and there were 9 treatment groups with 3 repetitions. The treatment in this study was kecapi leaves extract concentration of 10%, 20%, 30%, 40%, 50%, 60%, and 70%, the positive control was metronidazole gel 25% and the negative control was aquadest. The antibacterial test used the liquid dilution method to determine the value of Minimum Inhibitory Content (MIC) and solid dilution to determine the value of Minimum Bactericidal Content (MBC). Results: Based on the results and data analysis, it was found that kecapi leaf extract had a Minimum Inhibitory Content (MIC) at a concentration of 10% and a Minimum Inhibitory Content (KBM) at a concentration of 30%. Conclusion: Kecapi leaves extract (Sandoricum koetjape Merr) concentration of 10%, 20%, 30%, 40%, 50%, 60%, and 70% has antibacterial effectiveness against the growth of Aggregatibacter actinomycetemcomitans.Keywords: Aggregatibacter actinomycetemcomitans, Aggressive Periodontitis, Kecapi leaves ABSTRAKLatar belakang: Periodontitis agresif merupakan penyakit yang merusak jaringan periodontal dengan cepat yang disebabkan oleh dominasi bakteri Aggregatibacter actinomycetemcomitans sebesar 90%. Perawatan periodontitis agresif dapat berupa antibiotik. Salah satu antibiotik yang dapat dipakai yaitu metronidazol gel 25%, namun obat ini dapat memberikan efek samping apabila digunakan dalam jangka panjang. Terdapat tumbuhan herbal yaitu daun kecapi (Sandoricum koetjape Merr) yang mengandung senyawa yang dapat digunakan sebagai antibakteri diantaranya saponin, alkaloid, flavonoid, dan triterpenoid. Tujuan: Mengetahui efektivitas antibakteri ekstrak daun kecapi (Sandoricum koetjape Merr) konsentrasi 10%, 20%, 30%, 40%, 50%, 60%, dan 70% terhadap pertumbuhan bakteri Aggregatibacter actinomycetemcomitans. Metode: True experimental dengan desain post test only with control group dan terdapat 9 kelompok perlakuan dengan 3 kali pengulangan. Perlakuan pada penelitian ini yaitu ekstrak daun kecapi konsentrasi 10%, 20%, 30%, 40%, 50%, 60%, dan 70%, kontrol positif berupa metronidazol gel 25% dan kontrol negatif berupa akuades. Uji antibakteri menggunakan metode dilusi cair untuk mengetahui nilai Kadar Hambat Minimum (KHM) dan dilusi padat untuk mengetahui nilai Kadar Bunuh Minimum (KBM). Hasil: Berdasarkan hasil dan analisis data didapatkan bahwa ekstrak daun kecapi memiliki Kadar Hambat Minimum (KHM) pada konsentrasi 10% dan Kadar Bunuh Minimum (KBM) pada konsentrasi 30%. Kesimpulan: Ekstrak daun kecapi (Sandoricum koetjape Merr) konsentrasi 10%, 20%, 30%, 40%, 50%, 60%, dan 70% memiliki efektivitas antibakteri terhadap pertumbuhan bakteri Aggregatibacter actinomycetemcomitans.Kata Kunci : Aggregatibacter actinomycetemcomitans, Daun kecapi, Periodontitis Agresif