Lyophilized donor gut bacteria capsules for treating irritable bowel syndrome

Safety and Efficacy of Lyophilized Faecal Microbiota Transplantation Via Capsules in Treatment of Irritable Bowel Syndrome

Phase1; Phase2 Interventional University of Rijeka · NCT07481422

This trial will test whether taking oral freeze-dried fecal microbiota capsules can help adults 18–65 with IBS that hasn't responded to usual treatments.

Quick facts

PhasePhase1; Phase2
Study typeInterventional
Enrollment70 (estimated)
Ages18 Years to 65 Years
SexAll
SponsorUniversity of Rijeka Academic / other
Locations1 site (Rijeka)
Trial IDNCT07481422 on ClinicalTrials.gov

What this trial studies

This is a randomized, placebo-controlled phase 1/2 trial comparing lyophilized fecal microbiota transplantation (FMT) capsules to placebo capsules in adults with refractory IBS. Participants aged 18–65 with moderate to severe symptoms will be randomly assigned to receive capsules for three consecutive days, taking a proton pump inhibitor before the first dose and swallowing capsules under supervision. The trial measures changes in IBS symptom severity, quality of life, anxiety and depression scores, and records adverse events to compare safety between groups. The approach tests whether restoring gut microbial diversity with donor-derived, freeze-dried material can produce clinical improvement over placebo.

Who should consider this trial

Good fit: Adults 18–65 with an IBS-SSS score >175 whose symptoms have been refractory to conventional medical treatments and who pass screening tests (including negative coeliac disease evaluation) are ideal candidates.

Not a fit: Pregnant or breastfeeding people, those who are severely immunocompromised, or patients whose gastrointestinal symptoms are explained by another diagnosis are unlikely to benefit or are excluded.

Why it matters

Potential benefit: If successful, this treatment could reduce IBS symptoms and improve quality of life for patients who have not responded to standard therapies.

How similar studies have performed: Previous small trials of FMT for IBS, including some using oral capsules, have shown mixed results with occasional symptom improvements but no consistent, definitive benefit across studies.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* 18-65 years of age
* disease activity defined by an IBS-Symptom Severity Score (IBS-SSS) of more than 175
* symptoms refractory to conservative medical therapy (hyoscine salts, osmotic laxatives such as polyethylene glycol, loperamide, rifaximin, tricyclic antidepressants, SSRIs or other antidepressants, peppermint oil)
* negative evaluation for coeliac disease
* signed informed consent

Exclusion Criteria:

* pregnant or breastfeeding women
* women of childbearing potential who are unwilling to use an acceptable method of birth control
* severely immunocompromised or immunosuppressed (organ transplant recipients, those with neutropenia with an absolute neutrophil count of \<500 cells per mm3, those receiving current treatment with antineoplastic drugs, HIV positive)
* gastrointestinal symptoms explained by an alternative diagnosis (underlying IBD, infectious enteritis)
* severe allergy to capsule components
* therapy with new antidepressants or had a change in antidepressant dose within previous 3 months
* serious medical comorbidities (including neurological or psychiatric comorbidities)
* treatment with antibiotics 3 months before enrolment
* previous history of FMT at any time in the past
* unwillingness to ingest the capsules

Where this trial is running

Rijeka

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Irritable Bowel SyndromeFMTIBSLyophilization
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.