If you see any abnormalities in this area it is important to take your rabbit to a veterinarian for diagnosis and treatment. An anal polyp is an overgrowth of the mucus membrane within the rectum that protrudes through the anus. A polyp is almost always benign, although the possibility of it growing large enough to block the rectum does exist, in which case surgery is required to remove it. Polyps range in color from pink to red to brown and occur because of inflammation or changes in rectal or anal tissue. One example is a rabbit not getting enough fiber in her diet, which can change the shape or texture of the stool, which in turn can inflame the delicate tissue that rabbits have in this area. Multiple polyps can also be present, in which case you may see stool coming out from in between them.