Cirrhosis and small intestinal bacterial overgrowth: gut-liver axis dysregulation and clinical implications

Cirrhosis is the end stage of chronic liver disease and is prevalent worldwide. Small intestinal bacterial overgrowth (SIBO) is a condition characterised by aberrant microbial proliferation in the small intestine. It is closely associated with the development of multiple diseases. Studies have demonstrated that cirrhosis has a complex bidirectional relationship with SIBO. This review describes the epidemiological features of SIBO in patients with cirrhosis and delineates the mechanisms underlying their interaction through the gut-liver axis. Cirrhosis impairs intestinal motility, disrupts the intestinal barrier, and alters bile acid metabolism. These changes create a permissive environment for the development of SIBO. SIBO promotes bacterial translocation and triggers systemic inflammation. These processes exacerbate hepatic injury and compromise clinical outcomes. This review also summarises the current therapeutic strategies for SIBO to provide an evidence-based reference for clinical practice. Whether SIBO is an independent contributor to hepatic decompensation or primarily reflects advanced liver disease remains unresolved. Clarifying this distinction is essential for determining which patients with cirrhosis may benefit from targeted gut-liver axis interventions.