Cerbera odollam Gaertn. is a plant that known as suicide tree because of alkaloid compounds. Cerbera odollam Gaertn. leaves is used as a medicine and foodstufs in Indonesia. Extract of cerbera odollam leaves can be used as anti-cancer, antioxidant, anti-fungal, antifeedant, and antibacterial agent. This research aims to assess the potential of cerbera odollam leaves as an antibacterial agent. Cerbera odollam leaves will be extracted with etyl acetate with several extraction time (1, 3, 5, and 7 days). The crude extract from extraction will be diluted to concentration of 10, 20, 30, and 40% (w/v) then will be tested againts agar well diffusion method to four bacteria, namely S. aureus, B. cereus, E. coli, and P. aeruginosa. The time of extraction and concentration of the selected extract will be used for the stability test determined based on inhibition zone result. The stability of cerbera odollam leaves will be determined with heat treatment (60, 70, 80, and 90ᴼC; 10, 20, and 30 minutes), different pH levels (4, 5, 6, 7, and 8), NaCl concentration (1, 2, 3, and 4%), and glucose concentration (15, 20, 25, and 30%). The result showed that etyl acetate extract of cerbera odollam leaves with at least 3 days extraction 30% indicate inhibition zone more than 6 mm. The stability of cerbera odollam leaves extract with heat treatment at 70ᴼC for 10 minutes is the most stable than others treatment. The stability with pH level showed that the extract is most stable at pH 4 than others levels. The effect of antibacterial activity of NaCl addition is showed unstability of cerbera odollam extract. Glucose addition in the extract showed enhancement antibacterial activity along with replenishment of glucose concentration.