Diverticulosis is a condition where you have little "pockets" (diverticuli) lining the inside of your colon. They are a little like potholes, and you can imagine that seeds, popcorn shells and other debris can irritate the bottoms of these pockets and cause bleeding and inflammation. At times, the irritation (we call diverticulitis) can result in a rupture of a "pothole" and a pus collection (abscess) develops. The inflammation requires antibiotics and possibly abscess drainage by surgery or external tube. When the irritation leads to bleeding, we call this a diverticular bleed, and it is the most common cause of lower gastrointestinal bleeding in the elderly. The treatments for this bleeding are usually transfusions and time, but occasionally surgery or angiography (arterial dye study) are necessary.