Flow diagram of study selection.

Irritable Bowel Syndrome (IBS) is the most common functional gastrointestinal disorder. As one of the most common subtypes of IBS, IBS-D can impair the patients’ quality of life (QOL) and decreased work productivity. Acupuncture may be a potential treatment for patients with IBS-D. However, the treatment course of acupuncture was diverse. It is unclear what is the optimal acupuncture treatment courses for acupuncture. The efficacy and safety of different courses of acupuncture for IBS-D have not been systematically evaluated yet. The purpose of this study is to evaluate effectiveness of Acupuncture of different courses in the treatment of IBS-D and provide sufficient evidence for clinical recommendations for IBS-D. We will follow the Preferred reporting items for systematic reviews and meta-analysis protocols (PRISMA-P) guidelines to design the protocol of a systematic review and meta-analysis. This systematic review is registered in PROSPERO (CRD42023418846). We will include randomized controlled trials (RCTs) in which the efficacy of Acupuncture is compared with a placebo, sham acupuncture or Pinaverium bromide in the treatment of IBS-D with no language restrictions. The outcomes of interest will be efficiency rate and the Symptoms Severity Score. RCTs will be searched in the electronic database and Clinical Trials Registry Platform from inception to April 2023. Two independent reviewers will independently select studies, extract data from the included studies, and assess the risk of bias using the Cochrane tool. We will choose a random or fixed-effects model based on the heterogeneity index. We will use the relative risk and mean difference to estimate data with 95% CI. A stratified meta-analysis was conducted to evaluate the effect of different treatment courses of Acupuncture: 2weeks, 4weeks(or 1 months), 6 weeks, and 8 weeks. If there is significant clinical and methodological heterogeneity, we will look for the reason for heterogeneity and perform a subgroup analysis. According to the Grading of Recommendations Assessment, Development and Evaluation (GRADE), we will evaluate the evidence quality and provide the recommendation’s strength.