Objective <p>The aim of this study was to investigate the relationship between gut microbiota and non-small cell lung cancer (NSCLC) using bibliometric analysis and Two-Sample Mendelian Randomization (TSMR), and to elucidate the research trends and future directions in this field. The relationship between the intestinal microbiota and cancer has garnered growing scholarly interest; however, its precise role in non-small cell lung cancer (NSCLC) remains insufficiently understood.</p> Methods <p>This study conducted literature retrieval using the Web of Science Core Collection, performed bibliometric analysis and visualization using VOSviewer, CiteSpace, and the “bibliometrix” package in R software, and applied the Two-Sample Mendelian Randomization (TSMR) method to analyze the causal relationship between gut microbiota and NSCLC.</p> Results <p>The study found a total of 171 research papers focusing on the gut microbiota of non-small cell lung cancer patients from 2001 to 2023. Through bibliometric analysis, it examined the country and institution distribution, citing and cited journals, authors and co-cited authors, as well as identified significant citation bursts. The Two-Sample Mendelian Randomization analysis confirmed a significant association between Aminococcaceae abundance and non-small cell lung cancer, lung adenocarcinoma, and lung squamous cell carcinoma, suggesting its potential role as a low-risk factor.</p> Conclusions <p>This study identified an association between gut microbiota and non-small cell lung cancer, suggesting a potential risk-lowering effect of Aminococcaceae. However, further large-scale and high-quality research is needed to comprehensively investigate the causal relationship between gut microbiota and non-small cell lung cancer, taking into account the complex interactions between gut microbiota and the host, in order to better understand the pathogenesis of NSCLC.</p>