Small Intestinal Bacterial Overgrowth Syndrome (SIBO)Phase 4NCT07815548
Comparison of the Efficacy of Saccharomyces Boulardii and Rifaximin in the Treatment of Small Intestinal Bacterial Overgrowth
A Phase 4 study testing Saccharomyces boulardii sachets and Rifaximin (Xifaxan) in people with Small Intestinal Bacterial Overgrowth Syndrome (SIBO), run by Shandong University at 1 site in China.
Trial summary
This multicenter randomized controlled study aims to systematically evaluate the efficacy and safety of Saccharomyces boulardii sachets versus rifaximin in the treatment of small intestinal bacterial overgrowth (SIBO), with a focus on symptom relief and the impacts of anxiety-depressive factors on the treatment of… Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Small Intestinal Bacterial Overgrowth Syndrome (SIBO)
- What is being tested?
- Saccharomyces boulardii sachets and Rifaximin (Xifaxan)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 222 participants
- Where
- 1 siteChina
- Study dates
- 10 Sep 2026to 31 Dec 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 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Aged between 18 and 70 years, male or female.
- Presenting with chief complaints of abdominal distension and/or diarrhea.
- Diagnosis of small intestinal bacterial overgrowth (SIBO) confirmed by positive hydrogen-methane breath test.
Who cannot join
- Pregnant, puerperal, or breastfeeding women.
- Prior history of gastrointestinal malignancy or gastrointestinal surgery.
- Previously diagnosed or suspected lactose intolerance.
- Severe or extremely abnormal anxiety-depression scale scores.
- Confirmed extra-digestive system diseases, including urinary system diseases (e.g., chronic kidney disease), immune system diseases (e.g., scleroderma), nervous system diseases (e.g., Parkinson's disease), and endocrine system diseases (e.g., diabetes mellitus).
- Use of antibiotics or microecological preparations within 2 weeks before enrollment; receiving endoscopy, enema, or colonic barium-air contrast examination within 2 weeks before enrollment; use of prokinetics, secretagogues, antifoaming agents, antispasmodics, opioids, or antidepressants within 1 week before enrollment.
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- Known allergy to study medications.
- Immunosuppressed hospitalized patients or hospitalized patients with immune impairment due to critical illness.
- Unable or unwilling to provide written informed consent.
- History of psychiatric disorders.
- Any other conditions that render the subject inappropriate for participation in this study, as judged by the investigator.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
China1 site
Qilu Hospital of Shandong University
Jinan, Shandong, 250012
Xiuli Zuo, +86-18560080066, zuoxiuli@sdu.edu.cn
About this study
Official title: Comparison of the Efficacy of Saccharomyces Boulardii and Rifaximin in the Treatment of Abdominal Distension and Diarrhea Related to Small Intestinal Bacterial Overgrowth：a Non-inferiority Randomized Controlled Study
This multicenter randomized controlled study aims to systematically evaluate the efficacy and safety of Saccharomyces boulardii sachets versus rifaximin in the treatment of small intestinal bacterial overgrowth (SIBO), with a focus on symptom relief and the impacts of anxiety-depressive factors on the treatment of abdominal distension and diarrhea in SIBO patients. The findings will offer a new non-antibiotic therapeutic option for SIBO, especially for patients with antibiotic resistance or those requiring long-term management, and lay a theoretical foundation for the clinical application of intestinal microecological regulators.
- Being tested
- Saccharomyces boulardii sachets, Rifaximin (Xifaxan)
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Saccharomyces boulardii sachetsDrug
0.5 g, orally, twice daily for 2 weeks
Rifaximin (Xifaxan)Drug
0.4 g, orally, twice daily for 2 weeks
| Study group | Role | What they receive |
|---|---|---|
| Saccharomyces boulardii Sachets Treatment Arm | Experimental | Subjects receive Saccharomyces boulardii sachets 0.5 g twice daily orally for 2 weeks Receives: Drug: Saccharomyces boulardii sachets |
| Rifaximin Treatment Arm | Active comparator | Subjects receive rifaximin 0.4 g twice daily orally for 2 weeks Receives: Drug: Rifaximin (Xifaxan) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Clinical Effective Rate After Intervention and 1 Month Post-treatment
Proportion of participants achieving clinical effectiveness, defined as complete relief, major relief or partial relief of abdominal distension and diarrhea symptoms. Clinical effective rate = (number of participants with complete relief + major relief + partial relief) / total number of participants × 100%
Measured: End of 2-week treatment; 1 month after completion of treatment
Secondary outcomes (6)
Symptom Relief Rate After Intervention and 1 Month Post-treatment
Symptom relief rate calculated as [(pre-treatment total symptom score - post-treatment total symptom score) / pre-treatment total symptom score] ×100%. Symptom scores for abdominal distension and diarrhea are assessed by 4-level scoring systems
Measured: End of 2-week treatment; 1 month after completion of treatment
Change From Baseline in Gastrointestinal Symptom Rating Scale (GSRS) Total Score
GSRS is a 7-point Likert-type scale evaluating 15 gastrointestinal symptoms; total score ranges from 15 to 105, higher scores indicate more severe gastrointestinal symptoms. Change = post-treatment score minus baseline score
Measured: Baseline, end of 2-week treatment, 1 month after completion of treatment
Incidence of Adverse Events
Proportion of participants experiencing adverse events during the 2-week treatment period. Adverse events are graded per Common Terminology Criteria for Adverse Events Version 5.0 (CTCAE v5.0)
Measured: From first study drug administration up to 60 days after last study drug dose
Participant Treatment Adherence Rate
Treatment adherence defined as actual study drug consumption accounting for 80%-120% of prescribed dose. Adherence rate = number of participants with adequate adherence / total evaluable participants ×100%
Measured: Throughout the 2-week treatment period
Proportion of Participants With Comorbid Anxiety and Depression
Proportion of SIBO participants with abnormal anxiety-depression scores. Assessments include Self-rating Anxiety Scale (SAS), Self-rating Depression Scale (SDS), Hamilton Anxiety Rating Scale (HAMA), and Hamilton Depression Rating Scale (HAMD)
Measured: Baseline, 1 month after completion of treatment
Correlation Between Anxiety-depression Scores and Degree of Symptom Relief
Correlation analysis between baseline anxiety-depression scale scores and symptom relief rate after treatment
Measured: Baseline, 1 month after completion of treatment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Sep 2026
- Study start10 Sep 2026 (estimated)
- Primary completion30 Nov 2027 (estimated)
- Study completion31 Dec 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
- Masking
- None (open label)
- Enrolment
- 222 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Shandong University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Xiuli Zuo, Shandong University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07815548
- Sponsor's protocol ID
- KYLL-2025-12-010-1
- Status last verified
- Sep 2026
- First submitted
- 8 Sep 2026
- Last updated
- 15 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 15 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison of the Efficacy of Saccharomyces Boulardii and Rifaximin in the Treatment of Abdominal Distension and Diarrhea Related to Small Intestinal Bacterial Overgrowth：a Non-inferiority Randomized Controlled Study
- ClinicalTrials.gov ID
- NCT07815548
- Acronym / sponsor ID
- KYLL-2025-12-010-1
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 222 participants (estimated)
- Lead sponsor
- Shandong UniversityUniversity, hospital or other
- Study start
- 10 Sep 2026 (estimated)
- Primary completion
- 30 Nov 2027 (estimated)
- Study completion
- 31 Dec 2027 (estimated)
- First posted
- 11 Sep 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.
This multicenter randomized controlled study aims to systematically evaluate the efficacy and safety of Saccharomyces boulardii sachets versus rifaximin in the treatment of small intestinal bacterial overgrowth (SIBO), with a focus on symptom relief and the impacts of anxiety-depressive factors on the treatment of abdominal distension and diarrhea in SIBO patients. The findings will offer a new non-antibiotic therapeutic option for SIBO, especially for patients with antibiotic resistance or those requiring long-term management, and lay a theoretical foundation for the clinical application of intestinal microecological regulators.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Saccharomyces boulardii Sachets Treatment Arm | Experimental | Drug: Saccharomyces boulardii sachetsSubjects receive Saccharomyces boulardii sachets 0.5 g twice daily orally for 2 weeks |
| Rifaximin Treatment Arm | Active comparator | Drug: Rifaximin (Xifaxan)Subjects receive rifaximin 0.4 g twice daily orally for 2 weeks |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Aged between 18 and 70 years, male or female.
- Presenting with chief complaints of abdominal distension and/or diarrhea.
- Diagnosis of small intestinal bacterial overgrowth (SIBO) confirmed by positive hydrogen-methane breath test.
Key exclusion criteria (11 listed)
- Pregnant, puerperal, or breastfeeding women.
- Prior history of gastrointestinal malignancy or gastrointestinal surgery.
- Previously diagnosed or suspected lactose intolerance.
- Severe or extremely abnormal anxiety-depression scale scores.
- Confirmed extra-digestive system diseases, including urinary system diseases (e.g., chronic kidney disease), immune system diseases (e.g., scleroderma), nervous system diseases (e.g., Parkinson's disease), and endocrine system diseases (e.g., diabetes mellitus).
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 |
|---|---|---|
| Saccharomyces boulardii sachets0.5 g, orally, twice daily for 2 weeks | Drug | Saccharomyces boulardii Sachets Treatment Arm |
| Rifaximin (Xifaxan)0.4 g, orally, twice daily for 2 weeks | Drug | Rifaximin Treatment Arm |
Primary outcome
Clinical Effective Rate After Intervention and 1 Month Post-treatment
Time frame: End of 2-week treatment; 1 month after completion of treatment
Proportion of participants achieving clinical effectiveness, defined as complete relief, major relief or partial relief of abdominal distension and diarrhea symptoms. Clinical effective rate = (number of participants with complete relief + major relief + partial relief) / total number of participants × 100%
6 secondary outcomes
Symptom Relief Rate After Intervention and 1 Month Post-treatment
Time frame: End of 2-week treatment; 1 month after completion of treatment
Change From Baseline in Gastrointestinal Symptom Rating Scale (GSRS) Total Score
Time frame: Baseline, end of 2-week treatment, 1 month after completion of treatment
Incidence of Adverse Events
Time frame: From first study drug administration up to 60 days after last study drug dose
Participant Treatment Adherence Rate
Time frame: Throughout the 2-week treatment period
Proportion of Participants With Comorbid Anxiety and Depression
Time frame: Baseline, 1 month after completion of treatment
Correlation Between Anxiety-depression Scores and Degree of Symptom Relief
Time frame: Baseline, 1 month after completion of treatment
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 15 Sep 2026.
- Individual participant dataSharing planned: No
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Saccharomyces boulardii sachets and Rifaximin (Xifaxan) in people with Small Intestinal Bacterial Overgrowth Syndrome (SIBO), run by Shandong University at 1 site in China.
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 15 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. 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 Xiuli Zuo (+86-18560080066, zuoxiuli@sdu.edu.cn), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Clinical Effective Rate After Intervention and 1 Month Post-treatment (time frame: End of 2-week treatment; 1 month after completion of treatment). 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 15 Sep 2026.