Although the evidence base for clinical practices such as a low microbial diet, protective environments and clothing, and special skin antisepsis regimens is weak, some of these practices seem prudent and reasonable. Until further evidence is available, clinicians can use consensus guidelines and should assist in identifying clinical practices that require additional research. Ultimately, interventions with little or no demonstrated efficacy should be examined systematically or abandoned. Additional studies of sufficient sample size regarding nursing practices such as the role of protective environments, room placement, antiseptic bathing, and prevention and treatment of oral complications are indicated. Because of difficulties in randomization and risk stratification, rigorous observational studies often may be an acceptable alternative to clinical trials.