Dr. Moore points out that the overall incidence of pneumonia in our study (21.7%) exceeds the incidence of significant gastrointestinal bleeding and suggests that the benefit of gastric acid-reducing strategies may be outweighed by the risk for pneumonia in ventilated patients. We agree, although Dr. Moore should have more appropriately used for comparison the difference in the incidence of late-onset pneumonia between patients receiving pH-elevating agents (25 of 161 patients [16%]) and those receiving sucralfate (4 of 76 patients [5%]). In fact, our results suggest that sucralfate, an agent that does not modify gastric pH, may obviate the Hobson's choice mentioned by Dr. Moore: The incidence of macroscopic bleeding did not differ significantly among the three treatment groups (sucralfate, ranitidine, and antacids), but the incidence of late-onset pneumonia in patients receiving sucralfate was significantly less than that in the other two groups. Given the estimated risk reduction of 50% afforded by stress ulcer prophylaxis [1], a study using placebo in ventilated patients would be desirable but ethically questionable. In our study, 13 of 16 patients with gastrointestinal bleeding had median pH values greater than 4.0, as calculated with two daily measurements. As suggested by Dr. Moore, more detailed attention to gastric pH, including more frequent measurements, may help us to understand better the pathogenesis of gastrointestinal bleeding in these patients. While awaiting such studies, our results suggest that in high-risk patients (such as those who are ventilated), sucralfate might be as efficacious as pH-elevating agents for preventing gastrointestinal bleeding but may be associated with significantly fewer cases of late-onset pneumonia.