Enterococcus faecalis plays an important role in persistent endodontic infections, contributing to its high resistance to calcium hydroxide-Ca (OH) 2, the main intracanal medication in dentistry. In this context, the development of new antimicrobial formulations is of fundamental importance. Silver-containing nanomaterials have stood out, especially for their antimicrobial properties, and biogenic synthesis presents itself as an alternative to reducing the toxicity of nanoparticles (NPs). Thus, the objective of this research is to synthesize and evaluate the antibacterial potential of silver NPs with red propolis from Alagoas (NPsAg-PV) against E. faecalis. NPsAg-PV were synthesized by reducing silver salts by hydroalcoholic extract of red propolis from Alagoas (EHPV), characterized in the form of colloidal suspension by the technique of ultraviolet and visible spectrophotometry (UV-Vis), dynamic light scattering (EDL) and Zeta potential, followed by its incorporation into the Ca (OH) 2 paste. The spectral analysis showed absorbance at 425 and 421 nm, after 24 h and 72 h, respectively, values characteristic of the formation of silver Nps, the EDL showed a hydrodynamic diameter of 131.5 nm ± 1.19 and a polydispersion index (PDI) 0.266, suggesting the absence of agglomerated particles, the Zeta potential was -61 mV ± 1.59, indicating the stability of the silver colloid. Regarding the antimicrobial activity, the NPsAg-PV isolated and associated with the Ca (OH) 2 paste showed greater efficiency when compared to the Ca (OH) 2 paste. In pulp infection, bacteria organize themselves into biofilm, thus, it is expected that on E. faecalis biofilm, NPsAg-PV will also be effective. Nanotechnology has stood out for presenting new preventive and therapeutic possibilities, and this study can develop an innovative material for endodontic treatment.