Introduction Irritable bowel syndrome (IBS) is a common chronic functional gastrointestinal disorder that presents with abdominal pain/discomfort and altered bowel patterns. IBS has multiple potential causes for which conventional medicines have had limited success, resulting in a significant number of patients who do not sensitively respond to pharmacotherapy for a period of 12 months and who develop a continuing symptom profile (described as refractory IBS) and seek help through (non)pharmacological treatments. The aim of this study is to investigate the efficacy and safety of acupuncture therapy for refractory IBS on the basis of conventional treatments. Methods and analysis A total of 170 eligible patients who meet the Rome IV criteria for refractory IBS will be randomly allocated to receive acupuncture or sham acupuncture. Each patient will receive 12 sessions of acupuncture over 4 weeks and a 4-week follow-up. The primary outcome will be the IBS Symptom Severity Score. Secondary outcomes will include the proportion of participants experiencing adequate relief of global IBS symptoms, the weekly frequency of defecation, the stool properties assessed by the Bristol Grading Scale, the Work and Social Adjustment Scale, the IBS-Quality of Life score, and the Self-Rating Depression Scale and Self-Rating Anxiety Scale anxiety and depression scores. Outcome measures will be collected at baseline, 2 and 4 weeks of the intervention, and 6 and 8 weeks after the intervention. Categorical variables will be compared with Fisher’s exact test or the Wilcoxon rank-sum test, and continuous variables will be compared using Student’s t-test or the Wilcoxon rank-sum test. Ethics and dissemination The entire project has been approved by the ethics committees of Beijing University of Chinese Medicine (2020BZYLL0507) and Sichuan Province Regional Institution for Conducting Research on Traditional Chinese Medicine (2020KL-025). The outcomes of the trial will be disseminated through peer-reviewed publications. Trial registration number NCT04276961.

Background Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder characterized by abdominal pain, diarrhea or constipation, and changes in defecation patterns. No organic disease is found to explain these symptoms by routine clinical examination. This study aims to investigate the efficacy and safety of acupuncture therapy for IBS patients compared with those of conventional treatments. We also aim to identify the optimal acupoint combination recommended for IBS and to clarify the clinical advantage of the “multiacupoint co-effect and synergistic effect.” Methods and analysis A total of 204 eligible patients who meet the Rome IV criteria for IBS will be randomly stratified into acupuncture group A, acupuncture group B, or the control group in a 1:1:1 ratio with a central web-based randomization system. The prespecified acupoints used in the control group will include bilateral Tianshu (ST25) , Shangjuxu (ST37) , Neiguan (PC6) , and Zusanli (ST36). The prespecified acupoints used in experimental group A will include bilateral Tianshu (ST25) , Shangjuxu (ST37) , and Neiguan (PC6) . The prespecified acupoints used in experimental group B will include bilateral Tianshu (ST25) , Shangjuxu (ST37) , and Zusanli (ST36) . Each patient will receive 12 acupuncture treatments over 4 weeks and will be followed up for 4 weeks. The primary outcome is the IBS-Symptom Severity Scale (IBS-SSS) score. The secondary outcomes include the Bristol Stool Form Scale (BSFS), Work and Social Adjustment Score (WSAS), IBS-Quality of Life (IBS-QOL), Self-Rating Anxiety Scale (SAS), and Self-Rating Depression Scale (SDS) scores. Both the primary outcome and the secondary outcome measures will be collected at baseline, at 2 and 4 weeks during the intervention, and at 6 weeks and 8 weeks after the intervention. Ethics and dissemination The entire project has been approved by the ethics committee of the Beijing University of Chinese Medicine (2020BZYLL0903). Discussion This is a multicenter randomized controlled trial for IBS in China. The findings may shed light on the efficacy of acupuncture as an alternative to conventional IBS treatment. The results of the trial will be disseminated in peer-reviewed publications. Trial registration Chinese Clinical Trials Register ChiCTR2000041215 . First registered on 12 December 2020. http://www.chictr.org.cn/ .