This study investigates the role of the gut microbiome in the pathogenesis of chronic obstructive pulmonary disease (COPD) and explores the potential of faecal microbial transfer (FMT) and complex carbohydrates as therapeutic interventions. Using a mouse model of cigarette smoke (CS)-induced COPD, the researchers characterized the gut microbiota using metagenomics, proteomics, and metabolomics. They found that FMT alleviated key features of COPD, including inflammation, alveolar destruction, impaired lung function, and gastrointestinal pathology. The protective effects of FMT were additive to smoking cessation. The study also identified specific bacterial taxa, such as *Muribaculaceae*, *Desulfovibrionaceae*, and *Lachnospiraceae*, that correlated with disease severity. Proteomics and metabolomics analyses revealed downregulation of glucose and starch metabolism in CS-associated microbiota, which was restored by complex carbohydrate supplementation in both mice and human patients with COPD. A small pilot study in human patients with COPD found that inulin supplementation reduced symptoms and exacerbations, improved health-related quality of life, and altered the gut microbiota composition. These findings suggest that the gut microbiome plays a significant role in COPD pathogenesis and that targeted interventions, such as FMT and dietary modifications, may offer therapeutic benefits.This study investigates the role of the gut microbiome in the pathogenesis of chronic obstructive pulmonary disease (COPD) and explores the potential of faecal microbial transfer (FMT) and complex carbohydrates as therapeutic interventions. Using a mouse model of cigarette smoke (CS)-induced COPD, the researchers characterized the gut microbiota using metagenomics, proteomics, and metabolomics. They found that FMT alleviated key features of COPD, including inflammation, alveolar destruction, impaired lung function, and gastrointestinal pathology. The protective effects of FMT were additive to smoking cessation. The study also identified specific bacterial taxa, such as *Muribaculaceae*, *Desulfovibrionaceae*, and *Lachnospiraceae*, that correlated with disease severity. Proteomics and metabolomics analyses revealed downregulation of glucose and starch metabolism in CS-associated microbiota, which was restored by complex carbohydrate supplementation in both mice and human patients with COPD. A small pilot study in human patients with COPD found that inulin supplementation reduced symptoms and exacerbations, improved health-related quality of life, and altered the gut microbiota composition. These findings suggest that the gut microbiome plays a significant role in COPD pathogenesis and that targeted interventions, such as FMT and dietary modifications, may offer therapeutic benefits.