DysbiosisPhase 4NCT07852676
Effect of Bioflor on Gut Microbiota in Proton-Pump Inhibitor Users
A Phase 4 study testing Saccharomyces Boulardii 250 MG and Proton Pump Inhibitors (PPI) in people with Dysbiosis and Gastroesophageal Reflux Disease (GERD), run by Seoul National University Hospital at 3 sites in South Korea.
Trial summary
Proton-pump inhibitors (PPIs) are widely used to treat acid-related stomach problems, such as heartburn and acid reflux. Long-term use of PPIs has been linked to changes in the gut bacteria and fungi (called the gut microbiota), which may contribute to digestive side effects. Read more about this study
- Who is it for?
- Ages 19 to 79 yearsHealthy volunteers can take part
- Conditions the study is for
- Dysbiosis, Gastroesophageal Reflux Disease (GERD)
- What is being tested?
- Saccharomyces Boulardii 250 MG and Proton Pump Inhibitors (PPI)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 80 participants
- Where
- 3 sitesSouth Korea
- Study dates
- 18 Jul 2024to 18 Sep 2025
- Phase
- Phase 4
- Are there results?
- None posted in the registry
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 19 to 79 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Voluntary written informed consent to participate in this clinical trial
- Age 19 to 79 years
- No history of PPI use within 2 months prior to obtaining consent
- BMI between 18.5 and 30.0 kg/m², and body weight ≥ 50 kg
Who cannot join
- History of gastrointestinal or abdominal surgery
- Pregnant or breastfeeding women
- Immunocompromised individuals, or history of inflammatory bowel disease (Crohn's disease or ulcerative colitis)
- Antibiotic use within the prior 3 months
- Use of mucosal protective agents, NSAIDs, probiotics, or other agents/drugs altering gut microbiota function, lactulose, other antacids, GI motility-enhancing agents, or enemas within the prior 4 weeks
- Presence of a central venous catheter
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- Antifungal medication use within 14 days prior to enrollment
- History of Clostridioides difficile infection within 2 years prior to enrollment
- Significant change in dietary habits within 30 days prior to study participation, as assessed by the investigator
- Current smoker
- New drug prescription within 2 weeks prior to enrollment
- Any other condition that, in the investigator's judgment, makes the participant unsuitable for study participation
Trial locations and contacts
3 sites in 1 country.
South Korea3 sites
Department of Internal Medicine, Seoul National University Bundang Hospital
Seongnam-si, Gyeonggi-do, 13620
Division of Gastroenterology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine
Seoul, 03181
Department of Internal Medicine, Seoul Metropolitan Government Seoul National University Boramae Medical Center
Seoul, 07061
About this study
Official title: Effects of Saccharomyces Boulardii Probiotics (Bioflor®) on Gut Microbiota in Proton-pump Inhibitor User
Proton-pump inhibitors (PPIs) are widely used to treat acid-related stomach problems, such as heartburn and acid reflux. Long-term use of PPIs has been linked to changes in the gut bacteria and fungi (called the gut microbiota), which may contribute to digestive side effects. Bioflor® is a probiotic product containing a yeast called Saccharomyces boulardii, which has been used to help with various digestive problems. However, little is known about how Bioflor affects the gut microbiota in people who are taking PPIs.
This study enrolled three groups of adults at four hospitals/research centers in Korea: a control group without digestive symptoms who were not taking a PPI, a group of patients with reflux symptoms who started taking a PPI alone, and a group of patients who started taking a PPI together with Bioflor for 8 weeks. Participants completed symptom questionnaires and provided stool samples before and after treatment, which were analyzed to study changes in gut bacteria and fungi.
The purpose of this study was to compare gut microbiota composition and digestive symptoms between PPI users who did and did not take Bioflor, in order to better understand the role of Bioflor in people taking PPIs.
- Conditions
- Dysbiosis, Gastroesophageal Reflux Disease (GERD)
- Being tested
- Saccharomyces Boulardii 250 MG, Proton Pump Inhibitors (PPI)
- Keywords
- Proton pump inhibitor, Gut microbiome, Saccharomyces boulardii
- Medical subject headings
- Dysbiosis, Gastroesophageal Reflux
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Saccharomyces Boulardii 250 MGDrug
Saccharomyces boulardii was administered as Bioflor® 250 Cap. (Geon-il Pharm), a hard capsule formulation containing 282.5 mg of Saccharomyces boulardii (≥5×10⁹ viable cells) per capsule. Participants in the Bioflor group took 2 capsules orally, twice daily, for 8 weeks, in addition to their PPI treatment, regardless of meal timing but at consistent times each day.
Proton Pump Inhibitors (PPI)Drug
Proton-pump inhibitor was administered at a standard dose, orally, once daily for 8 weeks to participants in Case 1 and Case 2.
| Study group | Role | What they receive |
|---|---|---|
| Control | No intervention | Healthy participants without GERD symptoms or need for PPI treatment. The Control group is not subject to randomization. |
| Case1 | Active comparator | Patients with GERD/NERD symptoms starting PPI treatment, without Bioflor. Randomized 1:1 with Case 2. Receives: Drug: Proton Pump Inhibitors (PPI) |
| Case2 | Experimental | Patients with GERD/NERD symptoms starting PPI treatment combined with Bioflor (2 capsules twice daily for 8 weeks). Randomized 1:1 with Case 1. Receives: Drug: Saccharomyces Boulardii 250 MG; Drug: Proton Pump Inhibitors (PPI) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Fecal Microbiome Diversity
Microbial community diversity of fecal samples was assessed using both alpha diversity (within-sample diversity, measured by the Shannon index, observed species richness, and the Chao1 estimator) and beta diversity (between-sample diversity, measured by Bray-Curtis dissimilarity and Jaccard distance). Comparisons were made among the Control, Case 1 (PPI alone), and Case 2 (PPI plus Bioflor®) groups, including within-group changes from baseline to Week 8 in Case 1 and Case 2.
Measured: Baseline and Week 8 (Case 1, Case 2); Baseline only (Control)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Oct 2026
- Study start18 Jul 2024
- Primary completion18 Sep 2025
- Study completion18 Sep 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for DysbiosisStudies of the same condition, open and under way.
- More trials run by Seoul National University HospitalThe sponsor's other registered studies.
- 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
- This study employed a tri-arm parallel design. Case 1 and Case 2 were randomized in a 1:1 ratio. The Control group was not subject to randomization and was recruited separately according to eligibility criteria.
- Masking
- None (open label)
- Enrolment
- 80 participants (actual)
Sponsor and investigators
- Lead sponsor
- Seoul National University Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Kangbuk Samsung Hospital, Sungkyunkwan University, Seoul National University Boramae Hospital, Kuhnil Pharmaceutical Co., Ltd., National Research Foundation of Korea
- Responsible party
- Principal investigator, Cheol Min Shin, Seoul National University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07852676
- Sponsor's protocol ID
- B-2405-898
- Status last verified
- Jun 2026
- First submitted
- 25 Sep 2026
- Last updated
- 1 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 1 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Saccharomyces Boulardii Probiotics (Bioflor®) on Gut Microbiota in Proton-pump Inhibitor User
- ClinicalTrials.gov ID
- NCT07852676
- Acronym / sponsor ID
- B-2405-898
- Conditions
- Dysbiosis, Gastroesophageal Reflux Disease (GERD)
- Keywords
- Proton pump inhibitor, Gut microbiome, Saccharomyces boulardii
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 80 participants (actual)
- Lead sponsor
- Seoul National University HospitalUniversity, hospital or other
- Collaborators
- Kangbuk Samsung Hospital, Sungkyunkwan University, Seoul National University Boramae Hospital, Kuhnil Pharmaceutical Co., Ltd., National Research Foundation of Korea
- Study start
- 18 Jul 2024 (actual)
- Primary completion
- 18 Sep 2025 (actual)
- Study completion
- 18 Sep 2025 (actual)
- First posted
- 1 Oct 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.
Proton-pump inhibitors (PPIs) are widely used to treat acid-related stomach problems, such as heartburn and acid reflux. Long-term use of PPIs has been linked to changes in the gut bacteria and fungi (called the gut microbiota), which may contribute to digestive side effects. Bioflor® is a probiotic product containing a yeast called Saccharomyces boulardii, which has been used to help with various digestive problems. However, little is known about how Bioflor affects the gut microbiota in people who are taking PPIs.
This study enrolled three groups of adults at four hospitals/research centers in Korea: a control group without digestive symptoms who were not taking a PPI, a group of patients with reflux symptoms who started taking a PPI alone, and a group of patients who started taking a PPI together with Bioflor for 8 weeks. Participants completed symptom questionnaires and provided stool samples before and after treatment, which were analyzed to study changes in gut bacteria and fungi.
The purpose of this study was to compare gut microbiota composition and digestive symptoms between PPI users who did and did not take Bioflor, in order to better understand the role of Bioflor in people taking PPIs.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
- Model description
- This study employed a tri-arm parallel design. Case 1 and Case 2 were randomized in a 1:1 ratio. The Control group was not subject to randomization and was recruited separately according to eligibility criteria.
| Arm | Type | Receives |
|---|---|---|
| Control | No intervention | –Healthy participants without GERD symptoms or need for PPI treatment. The Control group is not subject to randomization. |
| Case1 | Active comparator | Drug: Proton Pump Inhibitors (PPI)Patients with GERD/NERD symptoms starting PPI treatment, without Bioflor. Randomized 1:1 with Case 2. |
| Case2 | Experimental | Drug: Saccharomyces Boulardii 250 MG, Drug: Proton Pump Inhibitors (PPI)Patients with GERD/NERD symptoms starting PPI treatment combined with Bioflor (2 capsules twice daily for 8 weeks). Randomized 1:1 with Case 1. |
Who may qualify
- Ages
- 19 to 79 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Voluntary written informed consent to participate in this clinical trial
- Age 19 to 79 years
- No history of PPI use within 2 months prior to obtaining consent
- BMI between 18.5 and 30.0 kg/m², and body weight ≥ 50 kg
Key exclusion criteria (12 listed)
- History of gastrointestinal or abdominal surgery
- Pregnant or breastfeeding women
- Immunocompromised individuals, or history of inflammatory bowel disease (Crohn's disease or ulcerative colitis)
- Antibiotic use within the prior 3 months
- Use of mucosal protective agents, NSAIDs, probiotics, or other agents/drugs altering gut microbiota function, lactulose, other antacids, GI motility-enhancing agents, or enemas within the prior 4 weeks
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 250 MGSaccharomyces boulardii was administered as Bioflor® 250 Cap. (Geon-il Pharm), a hard capsule formulation containing 282.5 mg of Saccharomyces boulardii (≥5×10⁹ viable cells) per capsule. Participants in the Bioflor group took 2 capsules orally, twice daily, for 8 weeks, in addition to their PPI treatment, regardless of meal timing but at consistent times each day. | Drug | Case2 |
| Proton Pump Inhibitors (PPI)Proton-pump inhibitor was administered at a standard dose, orally, once daily for 8 weeks to participants in Case 1 and Case 2. | Drug | Case1, Case2 |
Primary outcome
Fecal Microbiome Diversity
Time frame: Baseline and Week 8 (Case 1, Case 2); Baseline only (Control)
Microbial community diversity of fecal samples was assessed using both alpha diversity (within-sample diversity, measured by the Shannon index, observed species richness, and the Chao1 estimator) and beta diversity (between-sample diversity, measured by Bray-Curtis dissimilarity and Jaccard distance). Comparisons were made among the Control, Case 1 (PPI alone), and Case 2 (PPI plus Bioflor®) groups, including within-group changes from baseline to Week 8 in Case 1 and Case 2.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Oct 2026.
- Individual participant dataSharing planned: Undecided
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
3 sites 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 250 MG and Proton Pump Inhibitors (PPI) in people with Dysbiosis and Gastroesophageal Reflux Disease (GERD), run by Seoul National University Hospital at 3 sites in South Korea.
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 4 inclusion and 12 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: finished, as of the sponsor's last update on 1 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in South Korea. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Fecal Microbiome Diversity (time frame: Baseline and Week 8 (Case 1, Case 2); Baseline only (Control)). 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 1 Oct 2026.