Diverticulosis and diverticular disease of the colon are common conditions in Western countries. The incidence and prevalence of these diseases are increasing and becoming significant for health systems. A growing body of knowledge is shifting the paradigm of the pathogenesis and treatment of diverticular disease. Low-grade inflammation, altered intestinal microbiota, visceral hypersensitivity, and abnormal colonic motility have been identified as factors leading to diverticular disease. The risk of developing diverticulitis among individuals with diverticulosis is lower than 10 to 25%. Studies indicate that diverticular disease may become a chronic disorder in some patients, not merely an acute illness. Contrary to the advice from international guidelines, studies have not shown that a high-fiber diet protects against diverticulosis. The evidence about the use of antibiotics in uncomplicated diverticulitis is sparse and of low quality. In relation to surgery, studies support a more conservative approach to prophylactic surgery in patients with recurrent disease or chronic symptoms. Finally, new pathophysiological knowledge suggests that other treatments may be useful (mesalamine, rifaximin and probiotics). However, more research is necessary to validate the safety, effectiveness and cost-effectiveness of these strategies.