Clinical study on Shuchang Decoction's effect on intestinal gas in diarrhea-predominant IBS (Liver Depression and Spleen Deficiency Syndrome)

INTERVENTION: Shuchang Decoction group:One pack per day: Radi XBupleuri 9g, Radi XSaposhnikoviae 9g, processed Radi XCodonopsis 12g, processed Atractylodes 12g, Poria 12g, Pericarpium Citri Reticulatae 9g, processed Paeoniae Alba 12g, processed Glycyrrhiza 12g, Rhizoma Coptidis 6g, processed Zingiberis 9g. Concentrated granules requiring no decoction, to be taken orally twice daily.;Placebo group:One dose daily, composed of one‐tenth the original formula's dosage and a bitter agent, divided into two oral administrations.; CONDITION: DD91.01 Irritable Bowel Syndrome with Diarrhea (Liver Qi Stagnation and Spleen Deficiency Syndrome) PRIMARY OUTCOME: Irritable Bowel Syndrome Symptom Severity Scoring;Breath Analysis; SECONDARY OUTCOME: Traditional Chinese Medicine syndrome score;Abdominal pain/discomfort severity;Diarrhea Scoring;Irritable Bowel Syndrome Quality of Life Scale; INCLUSION CRITERIA: (1) Participants who meet the Rome IV diagnostic criteria for irritable bowel syndrome (IBS); (2) Individuals who have undergone colonoscopy within the past year with no abnormalities detected, or only hyperplastic polyps or tubular adenomas of the colon found; (3) Individuals aged between 18 and 70 years, with no gender restrictions; (4) Volunteers who agree to participate in this study and have signed the informed consent form, with the informed consent process conducted in accordance with GCP regulations.