IBS-D (Diarrhea-predominant)NCT07916688
Lactic Acid Bacteria in Functional Diarrheal Disorders
A study testing LL1500 in people with IBS-D (Diarrhea-predominant) and IBS (Irritable Bowel Syndrome), run by Szeged University at 1 site in Hungary.
Trial summary
The goal of this clinical trial is to learn whether a probiotic supplement can improve symptoms and quality of life in adults with diarrhea-predominant irritable bowel syndrome (IBS-D) or functional diarrhea (FD). These conditions can cause frequent loose stools, abdominal discomfort, and a lower quality of life. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- IBS-D (Diarrhea-predominant), IBS (Irritable Bowel Syndrome), Functional Diarrhea
- What is being tested?
- LL1500
- 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
- 1 siteHungary
- Study dates
- Nov 2026to Nov 2029
- Phase
- Interventional
- 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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults aged 18 years or older.
- Have diarrhea-predominant irritable bowel syndrome (IBS-D) or functional diarrhea (FD) diagnosed using Rome V criteria.
- Have had symptoms for at least 6 months.
- Have no warning signs that suggest another digestive disease.
- Have been taking the same treatment for IBS-D, FD, and other medical conditions for at least 1 month before joining the study.
- Are willing and able to provide written informed consent and follow study procedures.
Who cannot join
- Took antibiotics or probiotic products within the past 4 weeks.
- Had abdominal surgery in the past, except appendix removal (appendectomy).
- Have another type of irritable bowel syndrome or another functional digestive disorder.
- Have a known digestive disease that may explain their symptoms.
- Plan to start a new medication or change the dose of an existing medication during the study (except antispasmodic medications).
- Are unable or unwilling to complete study questionnaires and daily symptom records.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Hungary1 site, 1 recruiting
- Recruiting
University of Szeged
Szeged, 6725
Tamás Molnár, +36-62-545-189, molnar.tamas@med.u-szeged.hu
About this study
Official title: Efficacy of Lactic Acid Bacteria in Managing Diarrhea-Associated Functional Gastrointestinal Disorders: A Randomized Controlled Trial
The goal of this clinical trial is to learn whether a probiotic supplement can improve symptoms and quality of life in adults with diarrhea-predominant irritable bowel syndrome (IBS-D) or functional diarrhea (FD). These conditions can cause frequent loose stools, abdominal discomfort, and a lower quality of life.
The main questions this study aims to answer are:
Read more
- Does the probiotic improve quality of life compared with a placebo (a look-alike capsule that contains no active bacteria)?
- Does the probiotic help participants have more normal stool consistency and fewer bowel movements?
- Is the probiotic safe and well tolerated in people with IBS-D or FD?
Researchers will compare the probiotic supplement with a placebo to see whether the probiotic improves symptoms and quality of life.
Participants will:
- Take either the probiotic or placebo capsule once daily for 3 months.
- Switch to the other study treatment for an additional 3 months.
- Complete quality-of-life questionnaires at the start of the study, after 3 months, and after 6 months.
- Record the number of bowel movements each day throughout the study.
- Record stool consistency each day using the Bristol Stool Form Scale.
- Record daily pain during bowel movements using a Visual Analog Scale (VAS).
- Report any medications they take and any health problems that occur during the study.
The study will follow each participant for 6 months. Researchers hope the results will help determine whether this probiotic is a useful treatment option for people living with IBS-D or functional diarrhea.
- Being tested
- LL1500, Placebo Capsule
- Keywords
- IBS, IBS-D, FD, probiotic, supplement
- Medical subject headings
- Irritable Bowel Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
LL1500Dietary supplement
LL1500 is an oral probiotic supplement administered once daily as a gelatin capsule. Each capsule contains lyophilized Lactobacillus rhamnosus and Lactobacillus plantarum, providing at least 7.5 × 10⁹ colony-forming units (CFU) of each bacterial strain. Participants will receive LL1500 for a 3-month treatment period.
Placebo CapsuleOther
Matching oral placebo administered once daily as a gelatin capsule containing inactive excipients and no live bacterial strains. Participants will receive placebo for a 3-month treatment period.
| Study group | Role | What they receive |
|---|---|---|
| Experimental First Arm | Experimental | Participants randomized to this arm will receive LL1500, a probiotic supplement containing Lactobacillus rhamnosus and Lactobacillus plantarum, once daily for 3 months, followed by crossover to matching placebo for an additional 3 months under double-blind conditions. Receives: Dietary Supplement: LL1500; Other: Placebo Capsule |
| Placebo First Arm | Placebo comparator | Participants randomized to this arm will receive matching placebo once daily for 3 months, followed by crossover to LL1500, a probiotic supplement containing Lactobacillus rhamnosus and Lactobacillus plantarum, for an additional 3 months under double-blind conditions. Receives: Dietary Supplement: LL1500; Other: Placebo Capsule |
What is being measured
The primary outcome is the main question the study is designed to answer.
Irritable Bowel Syndrome Quality of Life (IBS-QOL) Total Score at 3 Months
IBS-specific quality of life assessed using the Irritable Bowel Syndrome Quality of Life (IBS-QOL) questionnaire. The IBS-QOL contains 34 items and yields a total score ranging from 0 to 100, with higher scores indicating better quality of life. The outcome measure is the change in total IBS-QOL score from baseline to 3 months.
Measured: Three months after enrollment
Secondary outcomes (5)
Irritable Bowel Syndrome Quality of Life (IBS-QOL) Total Score at 6 Months
IBS-specific quality of life assessed using the Irritable Bowel Syndrome Quality of Life (IBS-QOL) questionnaire. The IBS-QOL contains 34 items and yields a total score ranging from 0 to 100, with higher scores indicating better quality of life. The outcome measure is the change in total IBS-QOL score from baseline to 6 months.
Measured: Six months after enrollment
Mean Daily Stool Frequency at 3 Months
Mean number of bowel movements per day recorded by participants. The outcome measure is the change in average daily stool frequency from baseline to 3 months. Lower values indicate fewer bowel movements.
Measured: Three months after enrollment
Mean Daily Stool Frequency at 6 Months
Mean number of bowel movements per day recorded by participants. The outcome measure is the change in average daily stool frequency from baseline to 6 months. Lower values indicate fewer bowel movements.
Measured: Six months after enrollment
Mean Bristol Stool Form Scale Score at 3 Months
Stool consistency assessed using the Bristol Stool Form Scale, which ranges from Type 1 (hard stools) to Type 7 (watery stools). Types 3 to 5 are considered normal stool consistency. The outcome measure is the change in mean Bristol Stool Form Scale score from baseline to 3 months.
Measured: Three months after enrollment
Mean Bristol Stool Form Scale Score at 6 Months
Stool consistency assessed using the Bristol Stool Form Scale, which ranges from Type 1 (hard stools) to Type 7 (watery stools). Types 3 to 5 are considered normal stool consistency. The outcome measure is the change in mean Bristol Stool Form Scale score from baseline to 6 months.
Measured: Six months after enrollment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Nov 2026
- Study startNov 2026 (estimated)
- Primary completionNov 2028 (estimated)
- Study completionNov 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for IBS-D (Diarrhea-predominant)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 N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Participants will be randomized to receive either the probiotic or placebo for 3 months, followed by crossover to the alternate treatment for an additional 3 months. The study will use a double-blind design, with both participants and investigators masked to treatment allocation throughout the trial.
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Szeged University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07916688
- Sponsor's protocol ID
- NNGYK/09884-2/2026
- Status last verified
- Oct 2026
- First submitted
- 29 Oct 2026
- Last updated
- 4 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 4 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Efficacy of Lactic Acid Bacteria in Managing Diarrhea-Associated Functional Gastrointestinal Disorders: A Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT07916688
- Acronym / sponsor ID
- NNGYK/09884-2/2026
- Keywords
- IBS, IBS-D, FD, probiotic, supplement
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Szeged UniversityUniversity, hospital or other
- Study start
- Nov 2026 (estimated)
- Primary completion
- Nov 2028 (estimated)
- Study completion
- Nov 2029 (estimated)
- First posted
- 4 Nov 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.
The goal of this clinical trial is to learn whether a probiotic supplement can improve symptoms and quality of life in adults with diarrhea-predominant irritable bowel syndrome (IBS-D) or functional diarrhea (FD). These conditions can cause frequent loose stools, abdominal discomfort, and a lower quality of life.
The main questions this study aims to answer are:
- Does the probiotic improve quality of life compared with a placebo (a look-alike capsule that contains no active bacteria)?
- Does the probiotic help participants have more normal stool consistency and fewer bowel movements?
- Is the probiotic safe and well tolerated in people with IBS-D or FD?
Researchers will compare the probiotic supplement with a placebo to see whether the probiotic improves symptoms and quality of life.
Participants will:
- Take either the probiotic or placebo capsule once daily for 3 months.
- Switch to the other study treatment for an additional 3 months.
- Complete quality-of-life questionnaires at the start of the study, after 3 months, and after 6 months.
- Record the number of bowel movements each day throughout the study.
- Record stool consistency each day using the Bristol Stool Form Scale.
- Record daily pain during bowel movements using a Visual Analog Scale (VAS).
- Report any medications they take and any health problems that occur during the study.
The study will follow each participant for 6 months. Researchers hope the results will help determine whether this probiotic is a useful treatment option for people living with IBS-D or functional diarrhea.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, care provider, investigator)
- Number of arms
- 2
- Model description
- Participants will be randomized to receive either the probiotic or placebo for 3 months, followed by crossover to the alternate treatment for an additional 3 months. The study will use a double-blind design, with both participants and investigators masked to treatment allocation throughout the trial.
| Arm | Type | Receives |
|---|---|---|
| Experimental First Arm | Experimental | Dietary Supplement: LL1500, Other: Placebo CapsuleParticipants randomized to this arm will receive LL1500, a probiotic supplement containing Lactobacillus rhamnosus and Lactobacillus plantarum, once daily for 3 months, followed by crossover to matching placebo for an additional 3 months under double-blind conditions. |
| Placebo First Arm | Placebo comparator | Dietary Supplement: LL1500, Other: Placebo CapsuleParticipants randomized to this arm will receive matching placebo once daily for 3 months, followed by crossover to LL1500, a probiotic supplement containing Lactobacillus rhamnosus and Lactobacillus plantarum, for an additional 3 months under double-blind conditions. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Adults aged 18 years or older.
- Have diarrhea-predominant irritable bowel syndrome (IBS-D) or functional diarrhea (FD) diagnosed using Rome V criteria.
- Have had symptoms for at least 6 months.
- Have no warning signs that suggest another digestive disease.
- Have been taking the same treatment for IBS-D, FD, and other medical conditions for at least 1 month before joining the study.
Key exclusion criteria (6 listed)
- Took antibiotics or probiotic products within the past 4 weeks.
- Had abdominal surgery in the past, except appendix removal (appendectomy).
- Have another type of irritable bowel syndrome or another functional digestive disorder.
- Have a known digestive disease that may explain their symptoms.
- Plan to start a new medication or change the dose of an existing medication during the study (except antispasmodic medications).
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 |
|---|---|---|
| LL1500LL1500 is an oral probiotic supplement administered once daily as a gelatin capsule. Each capsule contains lyophilized Lactobacillus rhamnosus and Lactobacillus plantarum, providing at least 7.5 × 10⁹ colony-forming units (CFU) of each bacterial strain. Participants will receive LL1500 for a 3-month treatment period. | Dietary supplement | Experimental First Arm, Placebo First Arm |
| Placebo CapsuleMatching oral placebo administered once daily as a gelatin capsule containing inactive excipients and no live bacterial strains. Participants will receive placebo for a 3-month treatment period. | Other | Experimental First Arm, Placebo First Arm |
Primary outcome
Irritable Bowel Syndrome Quality of Life (IBS-QOL) Total Score at 3 Months
Time frame: Three months after enrollment
IBS-specific quality of life assessed using the Irritable Bowel Syndrome Quality of Life (IBS-QOL) questionnaire. The IBS-QOL contains 34 items and yields a total score ranging from 0 to 100, with higher scores indicating better quality of life. The outcome measure is the change in total IBS-QOL score from baseline to 3 months.
5 secondary outcomes
Irritable Bowel Syndrome Quality of Life (IBS-QOL) Total Score at 6 Months
Time frame: Six months after enrollment
Mean Daily Stool Frequency at 3 Months
Time frame: Three months after enrollment
Mean Daily Stool Frequency at 6 Months
Time frame: Six months after enrollment
Mean Bristol Stool Form Scale Score at 3 Months
Time frame: Three months after enrollment
Mean Bristol Stool Form Scale Score at 6 Months
Time frame: Six months after enrollment
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 4 Nov 2026.
- Individual participant dataSharing planned: Yes
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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 study testing LL1500 in people with IBS-D (Diarrhea-predominant) and IBS (Irritable Bowel Syndrome), run by Szeged University at 1 site in Hungary.
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 6 inclusion and 6 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: looking for participants now, as of the sponsor's last update on 4 Nov 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 Hungary. 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. 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.
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 Tamás Molnár (+36-62-545-189, molnar.tamas@med.u-szeged.hu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Irritable Bowel Syndrome Quality of Life (IBS-QOL) Total Score at 3 Months (time frame: Three months after enrollment). 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 4 Nov 2026.