Ulcerative colitis (UC) is a chronic, non-specific inflammatory bowel disease. A vicious cycle driven by gut microbiota dysbiosis and disruption of the intestinal barrier is considered a key mechanism underlying its recurrent and refractory nature. Reduced microbial diversity, decreased beneficial bacteria, and increased pathogenic taxa lead to disturbances in metabolites such as short-chain fatty acids and tryptophan, which subsequently impair the mucus layer, tight junction proteins, and immune barrier function, further aggravating mucosal inflammation. According to traditional Chinese medicine (TCM), core pathogenic factors such as “turbidity‑toxin theory” play central roles in UC. Guided by these principles, TCM therapies intervene through multiple approaches, including reshaping gut microbial composition, enhancing the production of beneficial metabolites, and upregulating tight junction proteins. These actions contribute to breaking the aforementioned vicious cycle. This review systematically summarizes the interactions between gut microbiota and the intestinal barrier in UC, as well as the theoretical basis and modern biological mechanisms by which TCM exerts therapeutic effects. The findings provide a theoretical reference for the application of TCM in UC management and highlight its potential clinical value.

ulcerative colitis  /  gut microbiota  /  intestinal barrier  /  traditional Chinese medicine  /  gut microbiota imbalance