What is the most common cause of lower gastrointestinal bleeding?

Diverticulosis is indeed the most common cause of lower gastrointestinal bleeding, particularly in older adults. This condition occurs when small pouches or diverticula form in the wall of the colon, often due to increased intraluminal pressure from straining during bowel movements or low dietary fiber intake. When these pouches become inflamed or erode into blood vessels, they can lead to significant bleeding.

The prevalence of diverticulosis makes it a common finding in patients presenting with lower GI bleeding. In fact, the incidence of diverticular bleeding increases with age, and it is a primary consideration during the evaluation of patients with this symptom. In many cases, the bleeding can be self-limited, but it may also require further medical intervention if it is significant or recurrent.

While hemorrhoids can cause lower GI bleeding and colon cancer is a serious consideration, they are not as prevalent as diverticulosis in the general population. Gastric ulcers, on the other hand, are associated with upper gastrointestinal bleeding, which differentiates them from the focus on lower GI sources. Thus, diverticulosis stands out as the leading cause in this context.