There is much evidence from the history and from the geographic distribution of diverticular disease that it is the result of a deficiency of fiber, and in particular cereal fiber, in our modern over-refined diet. The symptoms of the uncomplicated form of the disease can be abolished or relieved by adding bran to the diets of the majority of patients. The low-residue diet formerly used to treat the disease is contraindicated, as it is the cause of the condition.