The aim of this work is to investigate the chemical composition of essential oils from Eucalyptus globulus leaves (E. globulus) by gas-chromatography coupled with mass spectrometry (GC/MS) method, and to evaluate their antioxidant capacity (DPPH radical scavenging effect, reducing power, and inhibition oflipid peroxidation activity) as well as their antibacterial activity, against periodontopathogenic and cariogenic bacterial species, using microdilution method in 96-well microplates.