Intestinal disease. Coloured X-ray of the duodenum of a 27 year old patient with diverticula of the duodenum (small intestine). Diverticula (red) are small pouch-like structures that protrude out of weak spots in the intestine wall. They are thought to be caused by a low-fibre diet and so are very common in the developed world. In most cases diverticula are symptomless and cause no problems. Occasionally the diverticula can become inflamed and infected, a condition called diverticulitis, causing abdominal pain and constipation. Treatment is with a high-fibre diet. Cover credit: ZEPHYR / SCIENCE PHOTO LIBRARY.