Clinical trials
Microbiota clinical trials
Below are recruiting microbiota clinical trials, each written for real people, not researchers. We’re tracking 408 recruiting studies, each written for real people, not researchers, below.
Recruiting studies
- NCT05623007Recruiting
Diet and gut bacteria study for vaccinated teens with COVID
This trial tests whether changing diet can shift gut bacteria in overweight or obese teens after COVID-19 vaccination. The goal is to see if dietary changes can affect health markers related to the gut and immune system.
Jakarta Pusat, DKI JakartaAges 12–17 - NCT05628987Recruiting
Gut bacteria study in men with sperm production problems
This trial looks at whether gut bacteria (microbiome) and lifestyle factors are linked to poor sperm production or sperm quality. You may be asked for stool, urine, and blood samples and to complete questionnaires about diet and habits to help researchers understand possible connections.
Guangzhou, GuangdongAges 18–45 - NCT05632497Recruiting
Testing gut microbiome changes in adults with anorexia
This study looks at how changing the gut bacteria (microbiome) may affect people hospitalized for anorexia nervosa. You may be eligible if you’re an adult with a very low BMI and meet the study’s timing and health requirements.
VillejuifAges 18 years+ - NCT05638269Recruiting
Study of gut bacteria in people with serious long-term illness
This study looks at the types of gut bacteria in people living in certain parts of China who have serious long-term (chronic) illnesses. The goal is to better understand how gut bacteria differ and may help doctors in the future tailor care.
Chaoyang, Beijing MunicipalityAges 18–75 - NCT05646901Recruiting
Study how gut bacteria may affect loss of eating control
This study looks at how gut bacteria and the brain may be involved when people struggle to control eating. It may help researchers understand the body’s signals behind eating control problems.
Girona, GironaAges 30–65 - NCT05654753RecruitingPhase 2/Phase 3
Fecal transplant for stubborn axial spondyloarthritis
This trial tests whether transplanting healthy stool bacteria (fecal microbiota transplantation) can reduce symptoms in people with axial spondyloarthritis (including ankylosing spondylitis) who are not improving enough with standard medicines. If you qualify, you may receive study capsules containing processed bacteria and be closely monitored for safety and symptom changes.
Boulogne-BillancourtAges 18–75 - NCT05655780Recruiting
Irinotecan care guided by tumor genes and gut bacteria
This study looks at whether a patient’s tumor genetic makeup and gut bacteria activity can predict how well irinotecan-based treatment works and what side effects they might have. It may help personalize treatment to improve survival and quality of life for people with metastatic or unresectable colon cancer.
Maastricht, LimburgAges 18 years+ - NCT05669846RecruitingPhase 2
FMT plus pembrolizumab for advanced lung cancer after prior treatment
This Phase 2 trial studies whether adding fecal microbiome transplant (FMT) to pembrolizumab can help people with advanced, PD-L1–positive non-small cell lung cancer that has returned or progressed after anti–PD-1/PD-L1 therapy. You may be asked to give new tumor tissue and undergo gut procedures, because the study aims to change gut bacteria to boost the immune response.
Pittsburgh, PennsylvaniaAges 18 years+ - NCT05695261RecruitingPhase 2
Oral microbiome capsules for peanut allergy in teens
This Phase 2 study tests whether taking capsules made from donor gut microbes is safe and can reduce allergic reactions to peanuts. It involves peanut allergy testing and close follow-up with stool samples and check-ins.
Boston, MassachusettsAges 12–17 - NCT05698862Recruiting
Study how gut bacteria affect brain and behavior
This study looks at how gut bacteria may influence brain function and behavior, through a chemical called GABA. It may help researchers understand brain–gut links, though it is not yet a treatment trial.
ReadingAges 18–50 - NCT05704413Recruiting
Biobank study using gut tissue in bowel disease
This study collects and stores digestive (bowel) tissue to better understand how gut bacteria may affect diseases like ulcerative colitis or Crohn’s disease. It may help researchers find future ways to improve care for people with these conditions.
ParisAges 18 years+ - NCT05723913Recruiting
Test functional foods on blood sugar and gut bacteria
This study looks at how eating specific functional foods affects blood sugar after meals and changes in gut bacteria. It may help people understand ways to support healthy blood sugar and digestion, but it’s not for people with diabetes.
Mexico City, Mexico CityAges 18–60 - NCT05726396RecruitingPhase 2
Microbiome therapy for steroid-resistant immune colitis
This Phase 2 pilot study tests a “restorative microbiota therapy” (RMT) to treat colitis caused by immune checkpoint inhibitors when standard treatments like steroids are not working. It aims to see if this approach is safe and practical, and may improve diarrhea and gut inflammation.
Brainerd, MinnesotaAges 18 years+ - NCT05740319Recruiting
Test stool transplant to treat irritable bowel syndrome
This trial studies fecal microbiota transplantation, which is transferring stool bacteria from a healthy donor to help rebalance gut microbes. If you have irritable bowel syndrome (IBS) that hasn’t improved after several standard treatments, this study may see whether it reduces your symptoms and is safe.
Shanghai, Shanghai MunicipalityAges 18–70 - NCT05754645Recruiting
Study of gut microbiome in weight-related pregnancy outcomes
This study looks at differences in the gut’s living microbes (microbiome) in people who are trying to conceive or are early in pregnancy, and how that may relate to pregnancy outcomes. It may help researchers understand whether microbiome changes are linked to healthier—or more complicated—pregnancies.
Rotterdam, South HollandAges 18–45 - NCT05790356Recruiting
Fecal transplant to treat rheumatoid arthritis symptoms
This study tests whether transferring stool from a screened healthy donor into the gut can improve rheumatoid arthritis (RA) in people whose RA is in remission or low activity. It’s mainly trying to change the gut bacteria to reduce RA symptoms or flare-ups.
London, OntarioAges 18 years+ - NCT05830591Recruiting
Gut microbiome study in autism in children
This trial studies differences in the gut bacteria (microbiome) between children with autism and healthy children. It may help researchers understand what roles the gut may play in autism and guide future treatments.
TriesteAges 1–17 - NCT05930496Recruiting
Exercise after colorectal cancer to change gut bacteria
This study tests whether a structured exercise program can improve the makeup of gut microbiota (gut bacteria) in people who have finished treatment for stage II–III colorectal cancer. It may help learn how exercise supports recovery, and it involves remote or in-person sessions with gut-focused tracking.
Seattle, WashingtonAges 18–70 - NCT05931536Recruiting
How diet, stress, and thinking affect the gut
This study looks at how what you eat and your stress level may change thinking and the bacteria in your gut. It may help researchers understand links between lifestyle, brain function, and gut health.
CorkAges 18–50 - NCT05931562Recruiting
How diet may change gut bacteria and brain signals
This study looks at how changing your diet affects the gut bacteria and how that may influence brain-related signals. It may help researchers understand whether diet could support overall brain and gut health.
CorkAges 18–50 - NCT05946083RecruitingPhase 2
Study links binge drinking, gut bacteria, and brain function
This Phase 2 study looks at how binge drinking may change gut bacteria and how your brain works. You may qualify if you’re a Portuguese-speaking student and your drinking pattern and health history match the study rules.
Braga, Gualtar, BragaAges 18–23 - NCT06001619RecruitingPhase 4
Prostate medication, metabolism, and gut bacteria
This study looks at how prostate medication affects your metabolism and the helpful bacteria in your gut. It may help explain how these drugs work and how they affect your body.
TurkuAges 18 years+ - NCT06030752RecruitingPhase 1
Fecal transplant for autism and ADHD in children
This study tests whether transferring healthy bacteria into the gut (called a fecal transplant) can improve symptoms of autism and ADHD in children and teens. It may help by fixing gut health problems that can affect behavior.
Nanjing, JiangsuAges 3–17 - NCT06050148RecruitingPhase 2/Phase 3
Fecal Transplant to Prevent Repeat Urinary Tract Infections
This trial tests whether a fecal microbiota transplant (a procedure that transfers healthy bacteria from a donor's stool into your gut) can help prevent repeat urinary tract infections in women who have frequent infections.
HelsinkiAges 18–90
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Common questions
- Are there clinical trials for microbiota?
- Yes. Clin2 currently lists 408 recruiting microbiota studies from the U.S. registry, each rewritten for real people, not researchers, so you can see what it’s testing and who it’s for.
- How do I know if I qualify for a microbiota trial?
- Each study lists its eligibility criteria — rules about age, diagnosis, and prior treatments. On every Clin2 trial page we explain these in words written for real people and offer a short, optional pre-screen for a fit read. The study team makes the final decision.
- Does it cost anything to join a microbiota trial?
- Using Clin2 is always free. Many trials cover the cost of the study treatment and related visits; some reimburse travel. The study team explains exactly what’s covered before you decide.
Related conditions
Clin2 helps you find and understand clinical trials and does not provide medical advice. Study data comes from ClinicalTrials.gov. Talk with your doctor about whether a specific trial is right for you.