Alterations in the colonic microbiome have long been implicated in several intestinal disease processes including IBD and cancer. Colonic diverticulosis is common, affecting up to 70% of people by the 8th decade. However, fewer than 5% of affected individuals will go on to develop acute diverticulitis (AD). The reason why only a small minority develop AD is uncertain but may be related to alterations in their colonic microbiome. This talk discusses the current body of evidence for microbiome alterations being associated with AD, including the results of a study performed locally.