BackgroundDachaihu Decoction (DCD) is a traditional herbal formula widely used for treating acute pancreatitis (AP) in China. However, the efficacy and safety of DCD has never been validated, limiting its application. This study will assess the efficacy and safety of DCD for AP treatment.MethodsRelevant randomized controlled trials of DCD in treating AP will be searched through Cochrane Library, PubMed, Embase, Web of Science, Scopus, CINAHL, China National Knowledge Infrastructure database, Wanfang Database, VIP Database, and Chinese Biological Medicine Literature Service System database. Only studies published between the inception of the databases and May 31, 2023 shall be considered. Searches will also be performed in the WHO International Clinical Trials Registry Platform, Chinese Clinical Trial Registry, and ClinicalTrials.gov. Preprint databases and grey literature sources such as OpenGrey, British Library Inside, ProQuest Dissertations & Theses Global, and BIOSIS preview will also be searched for relevant resources. The primary outcomes to be assessed will include mortality rate, rate of surgical intervention, proportion of patients with severe acute pancreatitis transferred to ICU, gastrointestinal symptoms, and the acute physiology and chronic health evaluation II score. Secondary outcomes will include systemic complications, local complications, the normalization period of C-reactive protein, length of stay in the hospital, TNF-α, IL-1, IL-6, IL-8, and IL-10 levels, and adverse events. Study selection, data extraction, and assessment of bias risk will be conducted independently by two reviewers using the Endnote X9 and Microsoft Office Excel 2016 software. The risk of bias of included studies will be assessed by the Cochrane "risk of bias” tool. Data analysis will be performed using the RevMan software (V.5.3). Subgroup and sensitivity analysis will be performed where necessary.ResultsThis study will provide high-quality current evidence of DCD for treating AP.ConclusionThis systematic review will provide evidence of whether DCD is an effective and safe therapy for treating AP.Trial registrationPROSPERO registration numberCRD42021245735. The protocol for this study was registered at PROSPERO, and is available in theS1 Appendix.https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021245735.