Efficacy and Mechanistic Evaluation of Hewei Anchang Formula for Overlapping Gastrointestinal Symptoms in Patients With Coexisting Functional Dyspepsia and Diarrhea-Predominant Irritable Bowel Syndrome

1. To conduct a multicenter, randomized controlled trial across four hospitals to evaluate the efficacy of Hewei Anchang Formula in patients with overlapping gastrointestinal symptoms of functional dyspepsia (FD) and diarrhea-predominant irritable bowel syndrome (IBS-D), characterized by liver-stomach disharmony syndrome and liver stagnation-spleen deficiency syndrome, respectively. By leveraging the holistic regulatory effects of Chinese herbal formulas and the traditional Chinese medicine principle of "treating different diseases with the same therapeutic approach," this study aims to generate high-level evidence for the management of overlapping gastrointestinal symptoms in functional gastrointestinal disorders (FGIDs) and to establish a standardized and scalable therapeutic strategy. 2. To elucidate the potential mechanisms underlying the therapeutic effects of Hewei Anchang Formula on overlapping gastrointestinal symptoms of FD and IBS-D through multiple targets and pathways, with particular emphasis on modulation of the gut microbiota and the neuroendocrine-immune network.

Inclusion Criteria: 1. Meet the Rome IV diagnostic criteria for both functional dyspepsia (FD) and diarrhea-predominant irritable bowel syndrome (IBS-D). 2. Meet the diagnostic criteria for liver-stomach disharmony syndrome in FD and liver qi stagnation with spleen deficiency syndrome in IBS-D. 3. Aged 18-65 years, with no restriction on sex. 4. Fully informed about the study and voluntarily provide written informed consent. - Exclusion Criteria: 1. Severe primary diseases of the cardiovascular, hepatic, renal, hematologic, or respiratory systems, or malignant tumors. 2. Other organic gastrointestinal diseases, such as peptic ulcer or ulcerative colitis, or systemic diseases that may affect gastrointestinal motility, such as hyperthyroidism or diabetes mellitus. 3. Current or anticipated continuous use of medications that may affect gastrointestinal function, including prokinetic agents, antidiarrheal agents, antidepressants, anxiolytics, gut microbiota-modulating agents, and antibiotics. 4. A history of allergy to any study-related medication or a history of severe food allergy. 5. Psychiatric disorders, intellectual impairment, or language impairment. 6. Women who are planning pregnancy, pregnant, or breastfeeding. 7. Current participation in another drug clinical trial or participation in another drug clinical trial within the previous 4 weeks. 8. Severe anxiety or depression, as assessed using the Hospital Anxiety and Depression Scale (HADS). An anxiety subscale score of ≥15 is defined as severe anxiety, and a depression subscale score of ≥15 is defined as severe depression. Participants meeting the criterion for severe anxiety or severe depression on either subscale will be excluded. 9. A suspected or confirmed history of alcohol or drug abuse, or other circumstances that, in the investigator's judgment, may reduce the likelihood of enrollment or complicate study participation, such as frequent changes in the work environment that may increase the risk of loss to follow-up. -