Efficacy of Acupuncture-Mesalazine Combination Therapy in Ulcerative Colitis.

Inclusion Criteria: 1. documented diagnosis of UC； 2. age 18-75 years, regardless of gender; 3. mildly to moderately active UC, defined as a baseline total Mayo score between 3 and 10； 4. willing to receive the complete protocol of intradermal thumbtack needle embedding therapy (12 sessions across three treatment courses)； 5. Willing to undergo two colonoscopies (pre-treatment and post-treatment)； 6. complete all baseline assessments; 7. capable of understanding and voluntarily sign the informed consent form. Exclusion Criteria: 1. diagnosed with or suspected to have other type of inflammatory bowel disease, such as Crohn's disease; 2. patients in clinical remission or with severe disease activity ( baseline total Mayo score \< 3, or \> 10 ); 3. having severe gastrointestinal complications or a recent surgical history, including but not limited to: short bowel syndrome, toxic megacolon, intestinal perforation, complete intestinal obstruction, active massive gastrointestinal hemorrhage, or having undergone major abdominal or intestinal surgery within the past 6 months. 4. patients unwilling to undergo colonoscopy; 5. significant or unstable comorbidities (e.g., cardiovascular, respiratory, hepatic, or renal diseases); 6. patients with malignant tumors (including but not limited to colorectal cancer); 7. patients with a history of intradermal thumbtack needle embedding; 8. pregnant or lactating women; 9. patients with mental illness; 10. patients with either coagulation disorders or skin conditions (such as diseases, infections, ulcers, scars, or tumors at the acupuncture sites) that would preclude acupuncture； 11. strong needle phobia or unwillingness to receive acupuncture treatment; 12. any other condition (e.g., geographical remoteness, history of poor adherence) that, in the opinion of the investigator, would make the patient unsuitable for the study or likely to be non-compliant with the protocol.