BACKGROUND: Caffeic acid phenethyl ester (CAPE), a natural phenolic compound, has demonstrated antibacterial effects. Dental caries etiology is multifactorial, including a cariogenic biofilm containing multispecies bacteria. However, the antibacterial property of CAPE on multispecies biofilm is unclear. The aim of this study was to assess the effect of CAPE on the formation and cariogenicity in biofilm containing RESULTS: CAPE demonstrated a significant antimicrobial effect on