The antibacterial effects and mechanisms of 95% ethanolic extracts of Viscum articulatum were studied. The result showed that 95% ethanolic extracts of mistletoe had significant antagonistic activity against Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, and Micrococcus varians and had no effect on Bacillus subtilis and B. natto. The best antibacterial effect was observed in controlling Staphylococcus aureus (minimum inhibitory concentration (MIC): 0.1 mg/mL). Further studies showed that 95% ethanolic extracts increased the permeability of bacterial cell walls and membranes and caused the leakage of cellular contents such as soluble saccharides and proteins, thus increasing the conductivity. The observations from light microscopy, scanning electron microscopy, and transmission electron microscopy further demonstrated that the extracts could not only target the bacterial cell wall and membrane systems to destroy their normal structures, but also killed bacteria by inhibiting cell division. The results suggest that Viscum articulatum presents potential as a natural food additive.