Diverticular disease is a common disorder affecting 30-55% of the population in the developed world. It has been described as "a deficiency disease of Western civilization", a theory that has been proposed since it was observed that diverticular disease was uncommon in African and other developing countries where dietary fibre consumption was high. At the turn of the century the medical treatment of colonic diverticulosis involved the avoidance of "roughage", which was felt to exacerbate the problem. However, the use of high fibre diets in the prevention and treatment of the symptoms of diverticular disease has now become commonplace, and the development of this practice is discussed in this chapter.