Small Intestinal Bacterial Overgrowth Syndrome (SIBO)Phase 4SIBO-ProbioticNCT07426705
Effect of Multispecies Probiotic Supplementation on the Efficacy of Rifaximin α Therapy in Patients With Small Intestinal Bacterial Overgrowth (SIBO): a Randomized Placebo-controlled Trial
A Phase 4 study testing Probiotic preparation and Rifaximin (drug) in people with Small Intestinal Bacterial Overgrowth Syndrome (SIBO) and IBS, run by Państwowy Instytut Medyczny Ministerstwa Spraw Wewnętrznych i Administracji.
Trial summary
Small intestinal bacterial overgrowth (SIBO) is a common condition associated with gastrointestinal symptoms such as bloating, abdominal pain, diarrhea, and constipation, particularly in patients with irritable bowel syndrome. Antibiotic therapy with rifaximin is commonly used, but relapse rates remain high. Read more about this study
- Who is it for?
- Ages 18 to 75 years
- Conditions the study is for
- Small Intestinal Bacterial Overgrowth Syndrome (SIBO), IBS
- What is being tested?
- Probiotic preparation and Rifaximin (drug)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 100 participants
- Where
- No sites listed yet
- Study dates
- 15 Feb 2026to 15 Jul 2027
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age ≥18 years.
- Meets Rome IV criteria for irritable bowel syndrome.
- Written informed consent to participate in the study.
Who cannot join
- Lack of cooperation with investigators.
- Age >75 years.
- Need for modification of gastrointestinal treatment during the study.
- Use of antibiotics within 4 weeks before screening.
- Use of probiotics within 7 days before screening.
- Endoscopic examination within 6 weeks before screening or during the study without investigator approval.
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- History of abdominal surgery.
- Crohn's disease, ulcerative colitis, microscopic colitis, celiac disease, cystic fibrosis, chronic pancreatitis, liver cirrhosis, or end-stage renal disease.
- Low FODMAP diet within 4 weeks before screening.
- Pregnancy or breastfeeding.
- Lactulose intolerance.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
Aleksandra Perdek contact
About this study
Official title: Effect of Enterococcus Faecium and Bacillus Subtilis-Containing Multispecies Probiotic Supplementation on the Therapeutic Efficacy of Rifaximin α in Patients With Small Intestinal Bacterial Overgrowth (SIBO): a Prospective, Randomized, Placebo-controlled Trial
Small intestinal bacterial overgrowth (SIBO) is a common condition associated with gastrointestinal symptoms such as bloating, abdominal pain, diarrhea, and constipation, particularly in patients with irritable bowel syndrome. Antibiotic therapy with rifaximin is commonly used, but relapse rates remain high.
This randomized, placebo-controlled clinical trial aims to evaluate whether supplementation with a multispecies probiotic containing Enterococcus faecium and Bacillus subtilis improves the effectiveness of rifaximin therapy in adult patients with SIBO.
Read more
Participants will be randomly assigned to receive either rifaximin plus the probiotic or rifaximin plus placebo. Clinical assessments will include hydrogen breath testing and evaluation of gastrointestinal symptoms using standardized questionnaires at baseline and during follow-up visits.
The study is being conducted at a single academic medical center in Poland and is sponsored by Państwowy Instytut Medyczny MSWiA. The probiotic and rifaximin are provided by Urgo.
The results of this study may help determine whether probiotic supplementation can improve treatment outcomes and reduce recurrence of SIBO.
- Being tested
- Probiotic preparation, Placebo, Rifaximin (drug)
- Keywords
- SIBO, IBS, probiotic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Probiotic preparationDietary supplement
Oral probiotic preparation administered once daily for 6 weeks following completion of antibiotic treatment for small intestinal bacterial overgrowth (SIBO). The product contains a defined combination of bacterial strains and is intended to support restoration of gut microbiota and reduce recurrence of SIBO.
PlaceboOther
Matching oral placebo capsule administered once daily for 6 weeks following completion of antibiotic treatment for small intestinal bacterial overgrowth (SIBO). The placebo is identical in appearance, taste, and packaging to the probiotic product but contains no live microorganisms.
Rifaximin (drug)Drug
Rifaximin is administered to all participants as background standard therapy for SIBO at a dose of 1600 mg per day orally for 14 days. The randomized comparison concerns adjunctive probiotic versus placebo.
| Study group | Role | What they receive |
|---|---|---|
| Probiotic Group | Experimental | Participants will receive rifaximin followed by the probiotic preparation according to the study protocol. Receives: Dietary Supplement: Probiotic preparation; Drug: Rifaximin (drug) |
| Placebo Group | Placebo comparator | Participants will receive rifaximin followed by placebo according to the study protocol. Receives: Other: Placebo; Drug: Rifaximin (drug) |
What is being measured
The primary outcome is the main question the study is designed to answer.
SIBO eradication rate
Proportion of participants with eradicated small intestinal bacterial overgrowth (SIBO), defined as a negative hydrogen breath test, assessed 4 weeks after treatment initiation (rifaximin for 14 days plus probiotic for 4 weeks).
Measured: 4 weeks
Secondary outcomes (1)
SIBO recurrence rate after completion of probiotic therapy
Proportion of participants with recurrent SIBO, defined as a positive hydrogen breath test, assessed 4 weeks after completion of 6 weeks of probiotic supplementation following rifaximin treatment.
Measured: 10 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Feb 2026
- Study start15 Feb 2026 (estimated)
- Primary completion15 Jul 2027 (estimated)
- Study completion15 Jul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Small Intestinal Bacterial Overgrowth Syndrome (SIBO)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Randomized, double-blind, placebo-controlled, parallel-group design.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Państwowy Instytut Medyczny Ministerstwa Spraw Wewnętrznych i Administracji
- Sponsor type
- Other government
- Collaborators
- URGO Poland
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07426705
- Sponsor's protocol ID
- 34/BK/2025
- Other IDs
- 34/BK/2025
- Acronym
- SIBO-Probiotic
- Status last verified
- Feb 2026
- First submitted
- 16 Feb 2026
- Last updated
- 23 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 23 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Enterococcus Faecium and Bacillus Subtilis-Containing Multispecies Probiotic Supplementation on the Therapeutic Efficacy of Rifaximin α in Patients With Small Intestinal Bacterial Overgrowth (SIBO): a Prospective, Randomized, Placebo-controlled Trial
- ClinicalTrials.gov ID
- NCT07426705
- Acronym / sponsor ID
- SIBO-Probiotic / 34/BK/2025
- Keywords
- SIBO, IBS, probiotic
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Państwowy Instytut Medyczny Ministerstwa Spraw Wewnętrznych i AdministracjiOther government
- Collaborators
- URGO Poland
- Study start
- 15 Feb 2026 (estimated)
- Primary completion
- 15 Jul 2027 (estimated)
- Study completion
- 15 Jul 2027 (estimated)
- First posted
- 23 Feb 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Small intestinal bacterial overgrowth (SIBO) is a common condition associated with gastrointestinal symptoms such as bloating, abdominal pain, diarrhea, and constipation, particularly in patients with irritable bowel syndrome. Antibiotic therapy with rifaximin is commonly used, but relapse rates remain high.
This randomized, placebo-controlled clinical trial aims to evaluate whether supplementation with a multispecies probiotic containing Enterococcus faecium and Bacillus subtilis improves the effectiveness of rifaximin therapy in adult patients with SIBO.
Participants will be randomly assigned to receive either rifaximin plus the probiotic or rifaximin plus placebo. Clinical assessments will include hydrogen breath testing and evaluation of gastrointestinal symptoms using standardized questionnaires at baseline and during follow-up visits.
The study is being conducted at a single academic medical center in Poland and is sponsored by Państwowy Instytut Medyczny MSWiA. The probiotic and rifaximin are provided by Urgo.
The results of this study may help determine whether probiotic supplementation can improve treatment outcomes and reduce recurrence of SIBO.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Randomized, double-blind, placebo-controlled, parallel-group design.
| Arm | Type | Receives |
|---|---|---|
| Probiotic Group | Experimental | Dietary Supplement: Probiotic preparation, Drug: Rifaximin (drug)Participants will receive rifaximin followed by the probiotic preparation according to the study protocol. |
| Placebo Group | Placebo comparator | Other: Placebo, Drug: Rifaximin (drug)Participants will receive rifaximin followed by placebo according to the study protocol. |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Age ≥18 years.
- Meets Rome IV criteria for irritable bowel syndrome.
- Written informed consent to participate in the study.
Key exclusion criteria (11 listed)
- Lack of cooperation with investigators.
- Age >75 years.
- Need for modification of gastrointestinal treatment during the study.
- Use of antibiotics within 4 weeks before screening.
- Use of probiotics within 7 days before screening.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Probiotic preparationOral probiotic preparation administered once daily for 6 weeks following completion of antibiotic treatment for small intestinal bacterial overgrowth (SIBO). The product contains a defined combination of bacterial strains and is intended to support restoration of gut microbiota and reduce recurrence of SIBO. | Dietary supplement | Probiotic Group |
| PlaceboMatching oral placebo capsule administered once daily for 6 weeks following completion of antibiotic treatment for small intestinal bacterial overgrowth (SIBO). The placebo is identical in appearance, taste, and packaging to the probiotic product but contains no live microorganisms. | Other | Placebo Group |
| Rifaximin (drug)Rifaximin is administered to all participants as background standard therapy for SIBO at a dose of 1600 mg per day orally for 14 days. The randomized comparison concerns adjunctive probiotic versus placebo. | Drug | Placebo Group, Probiotic Group |
Primary outcome
SIBO eradication rate
Time frame: 4 weeks
Proportion of participants with eradicated small intestinal bacterial overgrowth (SIBO), defined as a negative hydrogen breath test, assessed 4 weeks after treatment initiation (rifaximin for 14 days plus probiotic for 4 weeks).
1 secondary outcome
SIBO recurrence rate after completion of probiotic therapy
Time frame: 10 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Feb 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Aleksandra Perdek contact
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Probiotic preparation and Rifaximin (drug) in people with Small Intestinal Bacterial Overgrowth Syndrome (SIBO) and IBS, run by Państwowy Instytut Medyczny Ministerstwa Spraw Wewnętrznych i Administracji.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 23 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Paulina PANUFNIK (477221420, paulina.panufnik@pimmswia.gov.pl), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
SIBO eradication rate (time frame: 4 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Feb 2026.