The use of natural antimicrobial agents is garnering attention due to consumer and producer awareness of health problems. This study found that the essential oil of A. galanga had strong bactericidal activity against both Gram-negative and Gram-positive bacteria. The bactericidal action of A. galanga oil was extremely rapid. Results of scanning electron microscopy observations suggested that A. galanga oil had antibacterial action probably as a result of its modification of the bacterial cell membrane, disrupting the membrane's permeability. This study suggested that the essential oil of A. galanga shows promise as a natural antimicrobial agent for use as a food preservative.