We can define large bowel obstruction as the mechanical or functional obstruction of the large intestine which prevents the normal passage of intraluminal content along its length. As most cases of large bowel obstruction don’t spontaneously resolve by themselves, early identification and intervention is important to prevent serious complications, such as ischemia, perforation, and death. It’s therefore vital that you have a good knowledge of how large bowel obstruction can present, how we investigate these patients, and how best to manage them. In this tutorial series, we’re going to focus on mechanical causes of large bowel obstruction, so when there’s a physical blockage of the GI tract. It is, however, important to be aware of the functional causes too, where obstruction occurs in the absence of a physical blockage of the GI tract, but these will be discussed on a separate tutorial. Large bowel obstruction accounts for approximately 2% of emergency surgical admissions. In the majority of cases, the large bowel obstruction is due to a mechanical cause of blockage, with the common causes being malignancy, diverticular stricture, and volvulus. However, in some instances, the obstruction may be due to functional causes, for example, a pseudo-obstruction. In keeping with the more frequent causes we mentioned, large bowel obstruction most commonly affects the ageing population.