Modulation of microbiota by traditional Chinese medicine in chronic inflammatory airway disease: a systematic review and meta-analysis of animal studies

Background A growing number of studies have indicated that traditional Chinese medicine (TCM) can regulate microbiota in chronic inflammatory airway disease (CIAD). Nevertheless, no systematic review or integrated analysis has summarized relevant evidence to date, limiting the clinical application of TCM in this field. Methods This study followed the PRISMA reporting guidelines. We systematically searched PubMed, EMBASE, the Cochrane Library and Web of Science for animal studies published from January 1, 2006 to January 5, 2026 exploring the effects of TCM on microbiota in CIAD. Microbial diversity indices and abundance data were extracted. Meta-analysis was performed using R version 4.5.0 with the meta for package (version 5.0.1), and risk of bias was assessed using the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) tool. Results A total of 25 studies published from 2016 to 2025 were included, 20 of which were enrolled into the meta-analysis. No statistically significant overall effect of TCM on the examined gut or airway alpha-diversity indices was identified after re-analysis using REML random-effects models with Hartung–Knapp adjustment. Several pooled estimates showed substantial heterogeneity and sensitivity to individual-study omission. Most included studies reported differences in beta diversity between model and TCM groups. Changes in airway and gut microbial relative abundance were heterogeneous across studies. High or unclear risk of bias was identified in most SYRCLE domains for the included studies. Conclusion Current preclinical evidence suggests that TCM may be associated with changes in airway and gut microbiota in CIAD animal models. However, the updated quantitative analyses did not demonstrate statistically significant overall effects on the alpha-diversity indices examined, and evidence concerning airway microbiota and microbial relative abundance remains heterogeneous. These findings should not be interpreted as evidence of microbiota restoration or therapeutic mechanisms. Well-designed studies with more standardized methodologies are warranted to clarify the impact of TCM on lung–gut axis microecology. Systematic Review Registration https://www.crd.york.ac.uk/prospero/ , identifier PROSPERO CRD420261385384.