Background:In the previous research propolis and curcumin have been reported to have biological activity as antibacterial. Both of those herbs can be developed as anti-oral biofilm mouthwash oral hygiene. Mouthwash is produced as nanoemulsion that promotes wide distribution throughout oral biofilm and effectively penetrates to target cell. Objective: This study aims to create the best mouthwash formulation with great physical characteristics and stability, and also proved as an anti-biofilm agent. Methods: Each propolis A.mellifera and curcumin Curcuma domestica Val. was formulated into a mouthwash using the combined method of homogenization, mixing and ultrasonication. There was a variation amount of Tween-80 and glycerin in each formulation to investigate its effect on stability. The proven formula with the greatest stability was continued to undergo antibiofilm assay. Results: Result of this study showed that formula with a ratio of Tween-80 and glycerin 2:1 (v/v) was found to be the best. Tween-80 and glycerin can't work as a single surfactant to produce stable nanoemulsion. Propolis and curcumin mouthwash showed in vitro antibiofilm activities against Streptococcus mutans, the primer colony in the biofilm. Propolis mouthwash reported has better effectiveness with the MIC of biofilm formation was 5% v/v and % inhibition of 48,54%, respectively. Conclusion:Nanoemulsion propolis mouthwash is proven to have the higher effectiveness in inhibiting biofilm formation than curcumin mouthwash. It suggested nanoemulsion propolis can be developed as good oral hygiene mouthwash that cansignificantly reduce the number of oral bacteria and inhibit their proliferation.