Background: Little is known about the involvement of gut microbiota in the disease course of diverticulitis and the potential benefits of manipulating the gut milieu. We propose to conduct a randomised placebo-controlled feasibility trial of faecal microbiota transplantation (FMT) given as capsules to patients with acute uncomplicated diverticulitis. Objectives: The objective is primarily to investigate the feasibility of clinical safety, explore efficacy associated with FMT in this patient population, and examine changes in patient-reported quality of life and the composition and function of the gut microbiota. Design: Study protocol for a randomised placebo-controlled trial. Methods and analysis: Participants with acute, uncomplicated diverticulitis, as confirmed by computed tomography (CT) scan, will be recruited from Odense University Hospital (Denmark) and randomly assigned to either the intervention group or the control group. The intervention group will consist of 20 patients who receive encapsulated FMT. The control group will also consist of 20 patients, receiving placebo capsules. Primary safety endpoint: Patient safety is monitored by (a) the number of re-admissions and (b) the number of adverse events within 3 months of FMT/placebo; Primary efficacy endpoint: Reduction in the proportion of patients treated with antibiotics within 3 months following FMT/placebo; Secondary outcome: Change from baseline to 3 months in the GI-QLI questionnaire. Results will be analysed using an intention-to-treat approach. Adverse events or unintended consequences will be reported. Ethics and discussion: This is the first study to investigate the safety and efficacy of FMT in patients with acute uncomplicated diverticulitis. The project has the potential to broaden the knowledge and literature on the role of the intestinal microbiota in diverticulitis, and we believe it will elevate our understanding of cause and effect. Trial registration: Informed consent is obtained from all participants. The study is approved by the regional ethics committee (ref. S-20230023) and the Danish Data Protection Agency (ref. 24/2435). The trial was registered on clinicaltrials.gov (NCT06254625) on 10th February 2024.

Safety and efficacy of faecal microbiota transplantation in patients with acute uncomplicated diverticulitis: study protocol for a randomised placebo-controlled trial