Therapeutic Aspects of Small Intestinal Bacterial Overgrowth in Irritable Bowel Syndrome

Rationale : Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders. One of the potentially significant pathophysiological factors in IBS is small intestinal bacterial overgrowth (SIBO), characterized by microbial imbalance in the small intestine. Objective : To review current data on therapeutic approaches to SIBO in patients with IBS. Methods : The review includes publications from PubMed, Scopus, Web of Science, Cochrane Library, and eLIBRARY.RU databases from 2019 to 2025. The selection included randomized clinical trials, meta-analyses, and systematic reviews focusing on the diagnosis and treatment of SIBO in the context of IBS. Studies with low levels of evidence or small sample sizes were excluded. Results : Analysis of the included sources showed that the prevalence of SIBO in IBS patients ranges from 30% to 85%, with the highest rates observed in the diarrheal subtype. Rifaximin is the most extensively studied antibacterial agent and is associated with a significant reduction in bloating, abdominal pain, and stool irregularities. A carbohydrate-restricted diet has demonstrated positive effects on stool frequency, consistency, and abdominal pain. Probiotics containing Bacillus subtilis and Bacillus coagulans have shown efficacy in alleviating abdominal pain and improving quality of life. Conclusion : The coexistence of IBS and SIBO requires a comprehensive diagnostic and therapeutic approach. Rifaximin remains the treatment of choice for antibacterial therapy. Dietary interventions and probiotics serve as effective adjunctive measures. Further research is needed to standardize diagnostics, stratify patients, and assess the long-term efficacy of combined treatment strategies.