Advances in Traditional Chinese Medicine interventions for influenza A based on the gut-lung axis: modern evidence for the exterior-interior relationship between the lung and large intestine

Influenza A virus (IAV) is a common respiratory pathogen that causes seasonal epidemics and severe infections, imposing substantial healthcare and economic burdens. IAV infection can disrupt the gut microbiota, and the resulting dysbiosis influences host status during both the early and later stages of infection. In recent years, Traditional Chinese Medicine (TCM) has shown considerable potential in the treatment of IAV. Guided by the TCM concept of the exterior-interior relationship between the lung and large intestine and integrated with contemporary research on the gut-lung axis, this review summarizes advances in the mechanistic and preclinical evidence of Chinese herbal formulas, individual compounds, and polysaccharides in influenza A and outlines mechanism-based research directions and translational insights to inform future exploration.