Lactic Acid Bacteria in Functional Diarrheal Disorders

October 29, 2026 updated by: Szeged University

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:

  • 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 Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
100

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • 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.

Exclusion Criteria:

  • 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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Experimental First Arm

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.
Dietary supplement: LL1500

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.

Other: Placebo Capsule

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.
Placebo Comparator: Placebo First Arm

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.
Dietary supplement: LL1500

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.

Other: Placebo Capsule

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.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
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.
Three months after enrollment

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Irritable Bowel Syndrome Quality of Life (IBS-QOL) Total Score at 6 Months
Time Frame: Six 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 6 months.
Six months after enrollment
Mean Daily Stool Frequency at 3 Months
Time Frame: Three months after enrollment

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.
Three months after enrollment
Mean Daily Stool Frequency at 6 Months
Time Frame: Six months after enrollment

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.
Six months after enrollment
Mean Bristol Stool Form Scale Score at 3 Months
Time Frame: Three months after enrollment

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.
Three months after enrollment
Mean Bristol Stool Form Scale Score at 6 Months
Time Frame: Six months after enrollment

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.
Six months after enrollment

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Defecation Pain Visual Analog Scale (VAS) Score at 3 Months
Time Frame: Three months after enrollment

Pain during defecation assessed daily using a Visual Analog Scale (VAS). Scores range from 0 to 10, where 0 indicates no pain and 10 indicates the worst imaginable pain. The outcome measure is the change in mean daily VAS score from baseline to 3 months.
Three months after enrollment
Defecation Pain Visual Analog Scale (VAS) Score at 6 Months
Time Frame: Six months after enrollment

Pain during defecation assessed daily using a Visual Analog Scale (VAS). Scores range from 0 to 10, where 0 indicates no pain and 10 indicates the worst imaginable pain. The outcome measure is the change in mean daily VAS score from baseline to 6 months.
Six months after enrollment
Treatment-Emergent Adverse Events
Time Frame: From enrollment through 6 months

Number of participants experiencing any adverse event reported during treatment with either the probiotic supplement or placebo. Adverse events will be collected throughout study participation.
From enrollment through 6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Szeged University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 1, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 29, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 29, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 4, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 4, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 29, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • NNGYK/09884-2/2026

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings