Diarrhea TravelersPhase 3NCT03535272
Bismuth Subsalicylate's Role in the Prevention of Travelers' Diarrhea
A Phase 3 study testing Bismuth subsalicylate in people with Diarrhea Travelers and Antibiotic Resistant Infection, run by Centers for Disease Control and Prevention at 1 site in United States.
Trial summary
The purpose of this study is to determine if the use of prophylactic bismuth subsalicylate (BSS) has an effect on the acquisition of travelers' diarrhea (TD) or antimicrobial resistance (AMR) genes in fecal samples among international travelers who departed from the United States to South East Asia, South Central… Read more about this study
- Who is it for?
- Ages 18 to 69 yearsHealthy volunteers can take part
- Conditions the study is for
- Diarrhea Travelers, Antibiotic Resistant Infection
- What is being tested?
- Bismuth subsalicylate
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 482 participants
- Where
- 1 siteUnited States
- Study dates
- 20 May 2018to 29 Apr 2026
- Phase
- Phase 3
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 69 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Be ≥ 18 and <70 years of age at the time of enrollment
- Sign an informed consent stating willingness to participate and comply with the study protocol
- Plan on leaving for an international trip ≥7 days after their pre-travel consultation
- Plan on traveling in country for ≥7 days but ≤21 days (21 day limit due to BSS duration recommendations and a lack of data on longer-term BSS use)
- Traveling to either South East Asia, South Central Asia, North Africa, or Sub-Saharan Africa for at least 7 days of their itinerary
- Be willing to complete an initial eligibility screening
- Be willing to complete questionnaires and provide biologic specimens (stool) within 7 days of departure and within 10 days after return
- Be willing to refrain from taking any pre-biotics, probiotic, synbiotic and/or herbal supplements throughout their study period
Who cannot join
- Are <18 years of age or >69 years of age
- Are traveling in country for <7 or >21 days
- Have known or suspected contraindications to taking BSS (including, but not limited to, travelers with kidney disease, diabetes, gout, a clotting disorder, or an allergy to any component of BSS)
- Are pregnant (via self-report), are planning to become pregnant, or may become pregnant during travel (not actively using contraception and are sexually active), or are breastfeeding
- Routinely take a medication known to interact with BSS (including, but not limited to, insulin, methotrexate, valproic acid, angiotensin-converting enzyme inhibitors, anticoagulants, or other salicylates)
- Have taken an antibiotic in the 30 days before departure
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- Have taken any medications that may lower one's ability to fight infection (e.g., steroids, monoclonal antibodies, etc.)
- Have previous diagnoses of immunocompromising conditions such as HIV/AIDS, complement deficiency, immunoglobulin deficiency, or undergoing active chemotherapy or participants with chronic gastrointestinal disorders, such as chronic diarrhea, irritable bowel syndrome (IBS), inflammatory bowel disease (i.e., Crohn's disease, ulcerative colitis), celiac disease, malabsorption syndromes, pancreatic insufficiency, gallbladder disease, or current gastrointestinal cancer
- Have had diarrhea anytime in the previous 30 days, have diarrhea at the pre-travel consultation, or develop diarrhea before departure
- Have been given doxycycline for malaria prophylaxis for the current trip (due to possible drug-drug interactions and decreased absorption of the doxycycline)
- Have an allergy to any component of the placebo tablets
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Bismuth Subsalicylate's Role in the Prevention of Travelers' Diarrhea and Impact on Acquisition of Gut Antimicrobial Resistance Genes
The purpose of this study is to determine if the use of prophylactic bismuth subsalicylate (BSS) has an effect on the acquisition of travelers' diarrhea (TD) or antimicrobial resistance (AMR) genes in fecal samples among international travelers who departed from the United States to South East Asia, South Central Asia, or Africa. Our hypotheses will be tested using a double-blinded, placebo controlled randomized clinical trial with participants from a pre-travel health clinic in the United States.
Read the detailed description
This study is a double-blind, placebo-controlled randomized clinical trial designed to evaluate the effectiveness of bismuth subsalicylate (BSS) in preventing travelers' diarrhea (TD) and its potential impact on the acquisition of antimicrobial resistance (AMR) genes and changes in the gut microbiome among international travelers.
Adult participants (18-69 years) planning travel from the United States to high-risk regions, including South East Asia, South Central Asia, and Africa, will be recruited from a pre-travel health clinic. Eligible participants will be randomized to receive either BSS (4 tablets twice daily; total daily dose approximately 2.1 g) or a matching placebo. Study medication will begin prior to arrival at the destination and continue throughout the duration of travel (up to 21 days).
Participants will complete standardized questionnaires before travel, daily during travel, and after returning to the United States. These questionnaires will capture information on medication adherence, gastrointestinal symptoms, development of TD, healthcare utilization, and adverse events. TD will be defined as three or more unformed stools within a 24-hour period, with or without associated symptoms.
To evaluate secondary objectives, participants will provide stool samples within 7 days prior to departure and within 10 days after return. These samples will be analyzed to assess acquisition of AMR genes using molecular methods and to evaluate changes in the gut microbiome, including the presence of enteric pathogens.
The primary objective is to determine whether prophylactic BSS reduces the incidence of TD among international travelers. Secondary objectives include assessing the impact of BSS on acquisition of AMR genes and evaluating changes in the gut microbiome associated with travel and intervention use.
Participants will be followed from enrollment through completion of post-travel data collection, with a total participation duration of approximately 4-6 weeks. Safety will be monitored through participant-reported adverse events collected during and after travel.
This study aims to provide evidence on a low-cost, widely available preventive strategy for TD and to better understand its potential role in reducing the spread of antimicrobial resistance associated with international travel.
- Conditions
- Diarrhea Travelers, Antibiotic Resistant Infection
- Being tested
- Bismuth subsalicylate, Placebo
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Bismuth subsalicylateDrug
Also called Pepto Bismol
Bismuth subsalicylate administered orally as tablets (4 tablets twice daily; total daily dose approximately 2.1 g) beginning prior to arrival at the travel destination and continued throughout the duration of travel (up to 21 days).
PlaceboDrug
Also called Placebo Oral Tablet
Matching oral placebo tablets administered twice daily, identical in appearance, taste, and packaging to bismuth subsalicylate, given for the duration of travel (up to 21 days).
| Study group | Role | What they receive |
|---|---|---|
| Intervention Group | Active comparator | Bismuth subsalicylate 4 tablets po bid (2.1 grams total of BSS) Receives: Drug: Bismuth subsalicylate |
| Placebo | Placebo comparator | Placebo oral tablet 4 bid Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Traveler's Diarrhea
Incidence of travelers' diarrhea, defined as self-reported occurrence of three or more unformed stools within a 24-hour period with or without associated gastrointestinal symptoms during travel or within 10 days after return.
Measured: Change from baseline through 10 days post-travel
Secondary outcomes (1)
Gut AMR Genes
Pre- and post-travel stools will be tested for the presence/absence of AMR genes. Data for this outcome measure are not yet analyzed. Results will be submitted when analyses are complete.
Measured: Once within 7 days (before travel); once within 10 days (after travel)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 May 2018
- Study start20 May 2018
- Primary completion1 Nov 2023
- Study completion29 Apr 2026
Why it stopped: Unable to reach target sample size.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Diarrhea TravelersStudies 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 3
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- This study will be conducted as a double-blinded, placebo-controlled randomized clinical trial.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 482 participants (actual)
Sponsor and investigators
- Lead sponsor
- Centers for Disease Control and Prevention
- Sponsor type
- US federal agency
- Collaborators
- Procter and Gamble, The New York Center for Travel and Tropical Medicine
- Responsible party
- Principal investigator, Kristina Angelo, Centers for Disease Control and Prevention
- Investigators
- Bradley Connor, MD, Principal investigator, The New York Center for Travel and Tropical Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03535272
- Sponsor's protocol ID
- 7082
- Status last verified
- Apr 2026
- First submitted
- 1 May 2018
- Last updated
- 22 May 2026
- Results posted
- Yes, on ClinicalTrials.gov
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Gibb RD, Brum JM, Sloan KJ, Pitz AM, Circello BT, Grayling RA. Revisiting the efficacy of bismuth subsalicylate for the prevention of traveller's diarrhoea. J Travel Med. 2025 Oct 1;32(6):taaf076. doi: 10.1093/jtm/taaf076.
PubMed 40720752
Study at a glance
From the registry record, last updated by the sponsor on 22 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Bismuth Subsalicylate's Role in the Prevention of Travelers' Diarrhea and Impact on Acquisition of Gut Antimicrobial Resistance Genes
- ClinicalTrials.gov ID
- NCT03535272
- Acronym / sponsor ID
- 7082
- Conditions
- Diarrhea Travelers, Antibiotic Resistant Infection
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Unable to reach target sample size.
- Enrolment
- 482 participants (actual)
- Lead sponsor
- Centers for Disease Control and PreventionUS federal agency
- Collaborators
- Procter and Gamble, The New York Center for Travel and Tropical Medicine
- Study start
- 20 May 2018 (actual)
- Primary completion
- 1 Nov 2023 (actual)
- Study completion
- 29 Apr 2026 (actual)
- First posted
- 24 May 2018 (actual)
- Results
- Posted 12 Mar 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to determine if the use of prophylactic bismuth subsalicylate (BSS) has an effect on the acquisition of travelers' diarrhea (TD) or antimicrobial resistance (AMR) genes in fecal samples among international travelers who departed from the United States to South East Asia, South Central Asia, or Africa. Our hypotheses will be tested using a double-blinded, placebo controlled randomized clinical trial with participants from a pre-travel health clinic in the United States.
Detailed description
This study is a double-blind, placebo-controlled randomized clinical trial designed to evaluate the effectiveness of bismuth subsalicylate (BSS) in preventing travelers' diarrhea (TD) and its potential impact on the acquisition of antimicrobial resistance (AMR) genes and changes in the gut microbiome among international travelers.
Adult participants (18-69 years) planning travel from the United States to high-risk regions, including South East Asia, South Central Asia, and Africa, will be recruited from a pre-travel health clinic. Eligible participants will be randomized to receive either BSS (4 tablets twice daily; total daily dose approximately 2.1 g) or a matching placebo. Study medication will begin prior to arrival at the destination and continue throughout the duration of travel (up to 21 days).
Participants will complete standardized questionnaires before travel, daily during travel, and after returning to the United States. These questionnaires will capture information on medication adherence, gastrointestinal symptoms, development of TD, healthcare utilization, and adverse events. TD will be defined as three or more unformed stools within a 24-hour period, with or without associated symptoms.
To evaluate secondary objectives, participants will provide stool samples within 7 days prior to departure and within 10 days after return. These samples will be analyzed to assess acquisition of AMR genes using molecular methods and to evaluate changes in the gut microbiome, including the presence of enteric pathogens.
The primary objective is to determine whether prophylactic BSS reduces the incidence of TD among international travelers. Secondary objectives include assessing the impact of BSS on acquisition of AMR genes and evaluating changes in the gut microbiome associated with travel and intervention use.
Participants will be followed from enrollment through completion of post-travel data collection, with a total participation duration of approximately 4-6 weeks. Safety will be monitored through participant-reported adverse events collected during and after travel.
This study aims to provide evidence on a low-cost, widely available preventive strategy for TD and to better understand its potential role in reducing the spread of antimicrobial resistance associated with international travel.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- This study will be conducted as a double-blinded, placebo-controlled randomized clinical trial.
| Arm | Type | Receives |
|---|---|---|
| Intervention Group | Active comparator | Drug: Bismuth subsalicylateBismuth subsalicylate 4 tablets po bid (2.1 grams total of BSS) |
| Placebo | Placebo comparator | Drug: PlaceboPlacebo oral tablet 4 bid |
Who may qualify
- Ages
- 18 to 69 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- Be ≥ 18 and <70 years of age at the time of enrollment
- Sign an informed consent stating willingness to participate and comply with the study protocol
- Plan on leaving for an international trip ≥7 days after their pre-travel consultation
- Plan on traveling in country for ≥7 days but ≤21 days (21 day limit due to BSS duration recommendations and a lack of data on longer-term BSS use)
- Traveling to either South East Asia, South Central Asia, North Africa, or Sub-Saharan Africa for at least 7 days of their itinerary
Key exclusion criteria (11 listed)
- Are <18 years of age or >69 years of age
- Are traveling in country for <7 or >21 days
- Have known or suspected contraindications to taking BSS (including, but not limited to, travelers with kidney disease, diabetes, gout, a clotting disorder, or an allergy to any component of BSS)
- Are pregnant (via self-report), are planning to become pregnant, or may become pregnant during travel (not actively using contraception and are sexually active), or are breastfeeding
- Routinely take a medication known to interact with BSS (including, but not limited to, insulin, methotrexate, valproic acid, angiotensin-converting enzyme inhibitors, anticoagulants, or other salicylates)
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 |
|---|---|---|
| Bismuth subsalicylateAlso: Pepto BismolBismuth subsalicylate administered orally as tablets (4 tablets twice daily; total daily dose approximately 2.1 g) beginning prior to arrival at the travel destination and continued throughout the duration of travel (up to 21 days). | Drug | Intervention Group |
| PlaceboAlso: Placebo Oral TabletMatching oral placebo tablets administered twice daily, identical in appearance, taste, and packaging to bismuth subsalicylate, given for the duration of travel (up to 21 days). | Drug | Placebo |
Primary outcome
Traveler's Diarrhea
Time frame: Change from baseline through 10 days post-travel
Incidence of travelers' diarrhea, defined as self-reported occurrence of three or more unformed stools within a 24-hour period with or without associated gastrointestinal symptoms during travel or within 10 days after return.
1 secondary outcome
Gut AMR Genes
Time frame: Once within 7 days (before travel); once within 10 days (after travel)
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 May 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 40720752Gibb RD, Brum JM, Sloan KJ, Pitz AM, Circello BT, Grayling RA. Revisiting the efficacy of bismuth subsalicylate for the prevention of traveller's diarrhoea. J Travel Med. 2025 Oct 1;32(6):taaf076. doi: 10.1093/jtm/taaf076.
- 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. This study is not recruiting at the moment.
Bradley Connor, MD principal investigator
The New York Center for Travel and Tropical Medicine
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Bismuth subsalicylate in people with Diarrhea Travelers and Antibiotic Resistant Infection, run by Centers for Disease Control and Prevention at 1 site in United States.
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 8 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: stopped early, as of the sponsor's last update on 22 May 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 United States. 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.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 12 Mar 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Traveler's Diarrhea (time frame: Change from baseline through 10 days post-travel). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03535272, which also lists 1 linked publication.
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 22 May 2026.