Guojun Liu, Linzi Chen, Maosen Guan, Ningkun Xiao
Background: Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental condition. Increasing studies examine whether gut microbiota alterations and the gut-brain axis are linked to ASD-relevant phenotypes. As the literature expands rapidly, a quantitative mapping is needed to clarify influential work and evolving themes. Objective: To map global research on ASD and the gut microbiota, identify major contributors and knowledge bases, and characterize thematic evolution and emerging fronts. Methods: We analyzed 1,391 English-language articles and reviews indexed in the Web of Science Core Collection (1999-2024). CiteSpace, VOSviewer, and R were used to evaluate publication trends, collaboration networks, co-citation structure, keyword clustering, and burst detection. Results: Publication output increased slowly before 2010 and accelerated after 2018. The United States and China were leading contributors and key collaboration hubs. The co-citation core was anchored by landmark experimental and translational studies, including work on microbiome-to-behavior links and microbiome-targeted interventions. Keyword clustering and timeline views highlighted three prominent thematic directions: fecal microbiota transplantation, Rett syndrome, and maternal immune activation. Recurrent and burst keywords emphasized the gut-brain axis, short-chain fatty acids, gastrointestinal symptoms, and oxidative stress. Recent burst terms, including obesity, major depressive disorder, and glutamate, suggest increasing connections to metabolic and broader psychiatric dimensions. Conclusion: ASD-microbiome research has shifted from descriptive comparisons toward mechanism-oriented and intervention-relevant questions. Future progress will benefit from standardized protocols, longitudinal designs, and multi-omics integration, together with rigorously designed trials to evaluate microbiome-targeted strategies.