Ethnopharmacological relevance: Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by non-specific inflammation. Managing UC presents significant challenges due to its chronic nature and high recurrence rates. Indigo naturalis has emerged as a potential therapeutic agent in clinical UC treatment, demonstrating advantages in alleviating refractory UC and maintaining remission periods compared to other therapeutic approaches.

Aim of review: This review aims to elucidate the potential mechanisms underlying the therapeutic effects of indigo naturalis in UC treatment, assess its clinical efficacy, advantages, and limitations, and provide insights into methods and strategies for utilizing indigo naturalis in UC management.

Materials and methods: Comprehensive data on indigo naturalis were collected from reputable online databases including PubMed, GreenMedical, Web of Science, Google Scholar, China National Knowledge Infrastructure Database, and National Intellectual Property Administration.

Results: Clinical studies have demonstrated that indigo naturalis, either alone or in combination with other drugs, yields favorable outcomes in UC treatment. Its mechanisms of action involve modulation of the AHR receptor, anti-inflammatory properties, regulation of intestinal flora, restoration of the intestinal barrier, and modulation of immunity. Despite its efficacy in managing refractory UC and prolonging remission periods, indigo naturalis treatment is associated with adverse reactions, quality variations, and inadequate pharmacokinetic investigations.

Conclusion: The therapeutic effects of indigo naturalis in UC treatment are closely linked to its ability to regulate the AHR receptor, exert anti-inflammatory effects, mcodulate intestinal flora, restore the intestinal barrier, and regulate immunity. Addressing the current shortcomings, including adverse reactions, quality control issues, and insufficient pharmacokinetic data, is crucial for optimizing the clinical utility of indigo naturalis in UC management. By refining patient-centered treatment strategies, indigo naturalis holds promise for broader application in UC treatment, thereby alleviating the suffering of UC patients.