Background: Despite various causes of mechanical obstruction, there appears to be a great deal of variation depending on geographical location and age. Geographically, postoperative adhesions and hernia have been documented as the most common aetiology of mechanical bowel obstruction in high-income and low-and-middle-income countries, respectively. Whether there has been a change in this trend in low- and middle-income countries is a matter of speculation in the surgical community. Therefore, to fill this knowledge gap, this study aims to systematically review the existing literature on the aetiology of mechanical bowel obstruction with a focus on understanding the most common cause of mechanical bowel obstruction in low- and middle-income countries in both paediatric and adult populations to guide surgical practice. Methodology and Analysis: This protocol was designed and written according to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-analysis Protocol 2015 (PRISMA-P 2015) statement. However, the results of the systematic review will be reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. We will consider studies published in English and French between 2002 and 2022 that reported on the aetiology of mechanical bowel obstruction in any age group in low- and middle-income countries. We will conduct a literature search using Ovid MEDLINE, Ovid Embase, CINAHL on EBSCO and Web of Science databases employing relevant subject headings, keywords and synonyms, which will be combined using Boolean operators to refine the search results. A hand search of references of retrieved literature will be conducted. The retrieved articles will be imported into Zotero for de-duplication. The resulting set of titles and abstracts will be uploaded to Rayyan (an AI-assisted online systematic review tool), where they will be double-checked to identify articles eligible for inclusion. Two independent reviewers will screen articles to be included and disagreement will be resolved by discussion or by a third reviewer as a tie-breaker. Also, data extraction will be done by one reviewer and confirmed by another. Critical appraisal to assess the quality of the included studies will be carried out by two independent reviewers using the Joanna Briggs Institute (JBI) tools. We anticipate that the eligible studies will be quite heterogeneous in terms of their design, outcomes of interest, populations and comorbidities. Therefore, results may be synthesised descriptively without meta-analysis using charts, graphs and tables. Where possible, we will conduct a sub-analysis using conceptual frameworks based on age, WHO regions and continents. Ethics and Dissemination: No ethical approval will be sought because the required data is already in the public domain. Findings will be published in peer-reviewed journals.

The authors have declared no competing interest.

The author(s) received no specific funding for this work.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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Ethetical aprroval is not required since it is systematic review protocol. The data is already in the public repository

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I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

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No datasets were generated or analysed during the current study. All relevant data from this study will be made available upon study completion.