In the last years, traditional pathologic mechanisms of acute diverticulitis are being questioned and replaced by more scientifically grounded hypotheses that strongly postulate an inflammatory origin. Local pro-inflammatory cytokines, microbiota shifts, disturbed neurological intestinal signalling due to alterations in colonic neuropeptides and abnormal colonic motility are all being proposed as potential etiologic factors. Recent publications, therefore, call into question the benefits of antibiotic treatment or episodes of acute diverticulitis, especially for mild episodes. Furthermore, recent international guidelines endorse this stance in their recommendations. Moreover, recent studies provide evidence regarding the security of treating patients with mild acute diverticulitis as outpatients.