Several observations from this trial are noteworthy. While the overall number of patients studied (n = 512) was large compared to those in other studies of oral decontamination with chlorhexidine, only approximately one third of patients enrolled in the trial were actually intubated and receiving mechanical ventilation. Previous studies8,9 have focused primarily on intubated patients. Additionally, the patient population studied was different than that found in many ICUs around the world, given the young age of the patients (average age, approximately 36 years), lack of significant medical comorbidities (< 2% with chronic cardiac or respiratory disease), and relatively low acute physiology and chronic health evaluation (APACHE) II scores. Another striking finding in the study was the lower than expected rate of hospital-acquired pneumonia in the control group of 7.7% compared to a rate of 21.7% in patients evaluated in the 3 months before and after the conclusion of the study. The authors speculate that this effect may be due to meticulous oral cleansing. However, this may also be an example of the so-called Hawthorne effect, in which subjects who are singled out for special attention have better outcomes simply due to the increased attention they receive, independent of the intervention performed. As expected, among mechanically ventilated patients, the rates of pneumonia were considerably higher (chlorhexidine group, 15.9%; potassium permanganate group, 18.1%), but the sample sizes may not have been large enough to detect a significant difference in VAP rates between these groups, given the relatively low number of intubated patients.