The performance of colonoscopy on patients admitted to hospital is a common occurrence. There are a variety of indications for inpatient colonoscopies ranging from acute gastrointestinal bleeding to iron deficiency anemia to occult blood positivity. The practice of colonoscopy for these patients has become relatively commonplace, with most physicians rapidly scheduling the procedure and, in fact, many booking the patient directly to the endoscopy unit and obtaining the full history and consent at the time of the procedure. This practice of inpatient colonoscopy clearly has some advantages with expedited assessment; however, there are a number of issues that limit the benefit of this procedure and may, in some cases, counterbalance the potential gain from the procedure. In the next two sections of 'Ask the Expert' we will present a 'Pro and Con' discussion for inpatient colonoscopy. In contradistinction to most 'Pro/Con' arguments, we have chosen to start with the limitations of colonoscopy in the setting of patients admitted to hospital. The opposing view will be presented in next month's Journal. There is a plethora of literature on inpatient colonoscopy that demonstrates benefit and safety (1-6). At first glance, it seems that colonoscopy is something that should be offered routinely to inpatients without hesitation. Although the benefit has been demonstrated in many studies, most of these have concerned themselves with acute gastrointestinal bleeding. There are a number of reasons why the physician should hesitate before proceeding with an urgent colonoscopy.