Although over half of patients over 65 years old will have diverticulosis, only a minority experience symptoms. These are often similar to those of irritable bowel syndrome with pain and disordered bowel habit, but differ in having an onset in the sixth to seventh decade. The underlying mechanisms include visceral hypersensitivity which maybe postinflammatory, but may also be due to altered central pain processing. Somatization is a useful clue to a predominantly central pathology, while its absence points to local causes including altered enteric nerves and mucosal immune activation. Treatments should be tailored to the individual patient who shows either predominantly peripheral or central abnormalities.