Digestive functional disorders are among the most frequent reasons for medical consultation and a significant source of medical wandering. Therapeutic management of these patients is difficult, particularly due to the absence of specific treatment linked to an incomplete understanding of the pathophysiological mechanisms. In a certain number of these patients, the symptoms are accompanied by a small intestinal bacterial overgrowth (SIBO). This entity, historically identified in specific post-surgical situations, seems finally very common and associated with very diverse pathologies. The diagnosis of SIBO is currently being made more accessible through the development of breathing tests. Therapeutic management, based mainly on antibiotic therapy and diet, remains to date largely empirical because it is based on few studies but the growing interest in SIBO should make it possible to identify effective treatments during robust clinical trials.