Selective Decontamination of Digestive Tract (SDD) One of the current hypotheses of nosocomial infection is that colonization of the nasopharynx and oropharynx predisposes patients to the development of nosocomial pneumonia, and the bacterial overgrowth in the intestinal tract increases gut wall permeability, leading to bacterial translocation and sepsis. Selective decontamination of the digestive tract (SDD), which aims to eradicate colonization of potential pathogens from the oropharynx and gastrointestinal tract, is one of the strategies to reduce ventilator associated pneumonia (VAP) and sepsis in critically ill patients. Controversy exists about the effectiveness of SDD in reducing mortality and preventing antibiotic resistance [4-6]. The present SDD regimens may create selective pressure and induce the emergence of methicillin-resistant Staphylococcus aureus (MRSA), Gram-negative bacilli harboring extended-spectrum β-lactamases (ESBL), and even Candida [7, 8]. Therefore, SDD research must aim to find an ideal regimen effective on most pathogens while leaving the anaerobic flora undisturbed.