Condition

Microbiota clinical trials and research

• 21Clinical trials
• 399NIH research projects
• 9Countries

Newest Microbiota clinical trials

All recruiting trials (21)

• Inulin Prebiotic for Perimenopausal Women with Overweight or Obesity

  This study tests whether 2 weeks of inulin can affect gut and vaginal microbes, heart health, and muscle health in perimenopausal women who are overweight or obese, using a crossover design.

  Recruiting George Washington University · Washington D.C., District of Columbia · NCT07724522

• Health effects of ultra-processed foods on appetite and cardiometabolic health

  This study tests whether a high ultra-processed food diet affects appetite and cardiometabolic health compared with a nutrient-matched low ultra-processed diet in adults who keep their weight stable.

  Recruiting Göteborg University · Gothenburg · NCT07634159

• Cranberry for gut and metabolic health in adults with overweight or obesity

  This study will test whether drinking a cranberry beverage can improve blood sugar control, insulin sensitivity, blood lipids, and gut microbiota in adults with overweight or obesity who have metabolic risk factors.

  Recruiting Laval University · Québec, Quebec · NCT07460856

• Gut microbiota in children with suspected brain tumors

  This will test whether stool samples can reveal gut microbiota differences in children aged 3–18 who are suspected of having a central nervous system (CNS) tumor.

  Recruiting Meyer Children's Hospital IRCCS · Florence, Firenze · NCT07417085

• Flourish: Early infant gut microbiome program for babies born by C-section

  This project tests whether microbiome analysis, education, and personalized recommendations can improve gut bacteria and reduce early immune-related markers in babies born by C-section aged 0–3 months.

  Recruiting Seeding Inc · Austin, Texas · NCT07333482

• Epilepsy and gut and mouth bacteria: linking microbiota to seizure medicine response

  This project will test whether differences in gut and mouth bacteria are linked to epilepsy type and change how well seizure medicines work in people newly diagnosed with epilepsy compared with healthy volunteers.

  Recruiting at 6 sites Karolinska Institutet · Gothenburg and 5 other locations · NCT07253701

• Restore a newborn's gut microbiota using the mother's microbes.

  This will test whether giving C-section newborns bacteria from their own mother or commercial probiotics helps their gut microbiota become more like babies born vaginally.

  Recruiting at 2 sites University of Helsinki · Helsinki and 1 other locations · NCT07212361

• Gut and tumor bacteria patterns in metastatic versus non-metastatic colorectal cancer

  This project will test whether bacteria in the gut and tumor differ between people whose colorectal cancer has spread and those whose cancer has not to see if bacterial signatures can help predict spread.

  Recruiting Sixth Affiliated Hospital, Sun Yat-sen University · Guangzhou, Guangdong · NCT07154173

• Exploring the tiny world inside the aortic valve during surgery

  This study tests the DNA and microbiota found in the blood and explanted aortic valve of patients undergoing valve replacement or repair.

  Recruiting University Hospital, Toulouse · Toulouse, France · NCT07075601

• Coenzyme Q10 toothpaste with daily Limosilactobacillus reuteri probiotics to improve gum health during pregnancy

  For pregnant women with gum disease, this will try whether adding a CoQ10 toothpaste and daily L. reuteri probiotic to regular cleanings reduces plaque and gum bleeding.

  Recruiting University of Pavia · Pavia, Lombardy · NCT07029360

• Examining breath markers in liver disease patients

  This study is trying to see if certain breath markers can help identify and understand the progression of liver disease in patients, especially those with cirrhosis.

  Recruiting at 3 sites Shanghai Zhongshan Hospital · Shanghai, Shanghai Municipality and 2 other locations · NCT06968234

• Investigating how endocrine disruptors affect gut bacteria and colorectal cancer risk

  This study is trying to see if certain chemicals that mess with hormones can change gut bacteria and increase the risk of colorectal cancer in people.

  Recruiting Poitiers University Hospital · Poitiers · NCT06809660

• Investigating how night shift work affects women's health during their menstrual cycle

  This study tests how working night shifts and lack of sleep affects the health of young women during different stages of their menstrual cycle.

  Recruiting Uppsala University · Uppsala, Uppsala County · NCT06683248

• Probiotics before cesarean section to improve recovery in pregnant women

  This study is testing if taking probiotics for a week before a cesarean section can help pregnant women recover faster after surgery.

  Recruiting at 2 sites Phase 1 Third Affiliated Hospital, Sun Yat-Sen University · Guangzhou, Guangdong and 1 other locations · NCT06347770

• Investigating gut microbiota in patients with limb lymphedema and recurrent infections

  This study looks at how the bacteria in the gut might be linked to limb lymphedema and repeated infections in patients to see if there are any important differences between those who have infections and those who don’t.

  Recruiting Fondazione Policlinico Universitario Agostino Gemelli IRCCS · Rome · NCT06228937

• Exploring the role of gut microbiota in anorexia nervosa

  This study looks at how the bacteria in the gut might be linked to anorexia nervosa in women aged 16-50 with a low body weight to see if it can help improve treatment options.

  Recruiting Norwegian University of Life Sciences · Ås, Ås · NCT06144905

• Effects of gut bacteria on weight loss in pancreatic cancer patients

  This study is testing how gut bacteria from pancreatic cancer patients and healthy people affect weight loss in mice to see if it can help understand cachexia in cancer patients.

  Recruiting University Hospital, Geneva · Geneva · NCT05606523

• Study of human organoids to understand host-microbe interactions

  This study is trying to see how the tiny organisms in our gut interact with our body by using samples from people getting endoscopies to grow mini versions of their intestines.

  Recruiting Insel Gruppe AG, University Hospital Bern · Bern · NCT05323357

• Exploring the role of immune cells and gut bacteria in idiopathic nephrotic syndrome

  This study is trying to see how immune cells and gut bacteria affect people with idiopathic nephrotic syndrome during kidney problems.

  Recruiting at 2 sites Nantes University Hospital · Nantes, Loire-Atlantique and 1 other locations · NCT04924712

• Testing a new catheter for better fluid collection during endoscopy

  This study is testing a new type of catheter to see if it can collect fluid from the small intestine more effectively during endoscopy for patients undergoing the procedure.

  Recruiting Cedars-Sinai Medical Center · Los Angeles, California · NCT04418258

• Vaginal microbiome exposure for newborns delivered by C-section

  This study is testing if exposing newborns delivered by C-section to their mother’s vaginal bacteria can improve their health and development over the first three years of life.

  Recruiting Phase 1/2 National Institute of Allergy and Infectious Diseases (NIAID) · Falls Church, Virginia · NCT03298334

NIH-funded research (newest 40 of 399)

Early-stage science funded by the US National Institutes of Health. Most of these projects don't enroll patients, but they show what is being worked on.

• Diet, gut microbiome, and immune health in adults with type 2 diabetes

  A study at Stanford is exploring how fermented foods and their molecules, like lactate, influence gut bacteria and the body's immune and inflammatory responses in adults with adult-onset diabetes.

  NIH research Stanford University · Stanford, United States · NIH-11596288

• Gut microbiome and Parkinson's disease: how gut bugs relate to symptoms and progression

  A multi-year study will look at gut bacteria and related markers in people with Parkinson’s disease to understand how the gut-brain connection may influence symptoms and progression.

  NIH research University of Chicago · Chicago, United States · NIH-11583671

• Gut-Brain Axis in Parkinson’s Disease: biomarkers and procedures to track progression

  A patient-focused program to study how gut health and the brain interact in Parkinson’s disease using biomarkers and clinical procedures.

  NIH research Rush University Medical Center · Chicago, United States · NIH-11582685

• Oral bacteria and brain metastasis: how the mouth may influence brain tumors

  A study exploring how oral microbes may affect brain metastases and patient outcomes, with potential to guide new microbiome-based approaches.

  NIH research H. Lee Moffitt Cancer Ctr & Res Inst · Tampa, United States · NIH-11527242

• How gut bacteria metabolites affect your immune system and allergies

  This project looks at how substances made by the gut microbiome influence the body’s immune responses to allergic diseases and intestinal infections.

  NIH research Weill Medical Coll of Cornell Univ · New York, United States · NIH-11520822

• Vitamin D, gut bacteria and dementia risk in older adults with HIV

  This work will look at whether low vitamin D and changes in gut bacteria are linked to higher dementia risk in older adults living with chronic HIV and similar community members.

  NIH research Henry Ford Health + Michigan State University Health Sciences · East Lansing, United States · NIH-11517874

• Restoring a special sugar to rebuild the gut and strengthen barriers in HIV

  This project tests a tiny sugar (α1,2-fucose) to help the gut barrier and gut microbes in people living with HIV, aiming to reduce inflammation and aging-related changes.

  NIH research Northwestern University · Chicago, United States · NIH-11471759

• Understanding how gut microbes influence cancer and immune responses

  A scientist at Rutgers is studying how the microbes in our gut affect cancer growth and the body’s response to cancer immunotherapy.

  NIH research Rutgers Biomedical and Health Sciences · Newark, UNITED STATES · NIH-11457151

• Gut bacteria and Lewy body dementia: how microbes may influence brain health

  A large NIH grant is testing how gut microbes affect Lewy body dementia and whether altering the gut microbiome could influence disease progression in a mouse model and potentially in people.

  NIH research Yale University · New Haven, United States · NIH-11449428

• Gut bacteria and lung immune cells shape viral lung infections

  A study explores how gut microbes affect lung immune cells and severity of respiratory viral infections to identify potential ways to reduce illness.

  NIH research Georgia State University · Atlanta, United States · NIH-11449351

• Gut-immune-brain link to anesthesia-related brain changes in AD mice

  A study in mice explores how gut bacteria and the immune system may drive brain changes and cognitive problems after anesthesia and surgery, with a focus on models of Alzheimer’s disease.

  NIH research Massachusetts General Hospital · Boston, United States · NIH-11429362

• Gut bacteria and Tuft-2 cells linked to early colorectal cancer risk in young Black Americans

  This grant aims to understand how gut microbes and Tuft-2 cells may predict aggressive colon adenomas in young Black adults who develop colorectal cancer.

  NIH research Cleveland Clinic Lerner Com-Cwru · Cleveland, United States · NIH-11425469

• Copper vs Levonorgestrel IUDs and vaginal health in young African women at risk for HIV

  A randomized study will compare copper and levonorgestrel IUDs to see how they affect vaginal microbiota and mucosal barriers in young African women living with HIV or at risk for HIV.

  NIH research Seattle Children's Hospital · Seattle, United States · NIH-11420467

• Gut bacteria, HIV, and alcohol: how microbes affect gut health in people with HIV

  This NIH grant studies how alcohol use and HIV together affect the gut’s bacteria and barrier, exploring a possible way to reduce gut inflammation in people living with HIV.

  NIH research Rush University Medical Center · Chicago, United States · NIH-11416474

• Vaginal microbiota transplant to promote Lactobacillus-dominant cervicovaginal communities

  A clinical trial tests whether transferring vaginal microbiota from healthy donors can establish Lactobacillus-dominant vaginal communities to reduce risks linked with bacterial vaginosis.

  NIH research Massachusetts General Hospital · Boston, United States · NIH-11411247

• Genes, gut bacteria, and choline in atrial fibrillation

  A study exploring how dietary choline, gut microbes, and the chemical TMAO may influence atrial fibrillation and related heart risks in people.

  NIH research Cleveland Clinic Lerner Com-Cwru · Cleveland, United States · NIH-11408653

• Illuminating the tiny gut world: mapping and guiding therapies for the small intestine microbiota

  A project from Stanford aims to map and understand the small intestine’s microbes to develop therapies that improve gut health and prevent diseases like Crohn’s and SIBO.

  NIH research Stanford University · Stanford, United States · NIH-11408533

• Gut bacteria and how they influence alcohol seeking and decisions

  This project looks at whether the bacteria living in the gut affect how people or animals seek alcohol and make decisions about drinking.

  NIH research University of Maryland Baltimore · Baltimore, United States · NIH-11404984

• Fecal transplant to help alcohol-related liver disease

  A clinical trial will test whether a standardized oral fecal microbiota transplant (FMT) capsule can help people with alcohol-related liver disease drink less and feel mentally better.

  NIH research Virginia Commonwealth University · Richmond, United States · NIH-11402247

• Gut bacteria changes after bariatric surgery and colorectal cancer risk

  This study will follow adults who had bariatric surgery to understand how changes in the gut microbiome and bile acids might influence colorectal cancer risk.

  NIH research Vanderbilt University Medical Center · Nashville, United States · NIH-11401981

• Colon mucus sugars and how they help keep gut bacteria and the colon healthy

  Researchers are looking at how sugar-coated mucus made by cells in the front part of the colon helps keep gut bacteria balanced and may protect people with ulcerative colitis or pouch inflammation.

  NIH research Oklahoma Medical Research Foundation · Oklahoma City, United States · NIH-11401680

• How gut bacteria affect AIDS-related Kaposi’s sarcoma and its treatment

  This project looks at how the bacteria in the body may influence KS cancer risk and treatment outcomes in people with HIV/AIDS.

  NIH research University of Pittsburgh at Pittsburgh · Pittsburgh, United States · NIH-11401413

• Enteric virus and gut microbes: how bacteria affect reovirus infection

  A study from UT Southwestern will explore how gut bacteria and their sugars influence reovirus infection in the intestine, using two closely related virus strains that respond differently to microbes.

  NIH research Ut Southwestern Medical Center · Dallas, United States · NIH-11400316

• How gut cells talk with gut bacteria to keep digestion balanced

  This grant looks at how intestinal cells influence gut bacteria to keep the gut healthy and minimize inflammation.

  NIH research Utah State Higher Education System--University of Utah · Salt Lake City, United States · NIH-11398273

• Accelerating microbiota recovery to protect against C. difficile

  A short-term NIH grant to test ways to speed up gut microbiome recovery after antibiotics to prevent dangerous C. difficile infections in adults.

  NIH research University of California at Davis · Davis, United States · NIH-11398249

• Role of oral bacteria on blood vessel health in diabetes

  This project looks at how gum disease and the bacteria in the mouth affect blood vessels and heart risk in adults with diabetes.

  NIH research Meharry Medical College · Nashville, United States · NIH-11398214

• Gut microbes and immune system growth of lymph vessels in health and disease

  A study from the University of Pittsburgh explores how gut bacteria influence immune-related lymph vessels and tissue structures, which may affect cancer, autoimmunity, IBD, and infections.

  NIH research University of Pittsburgh at Pittsburgh · Pittsburgh, United States · NIH-11398138

• National Fecal Microbiota Transplant (FMT) Registry

  This registry collects health and safety information from people who receive fecal microbiota transplants or related live-microbe treatments to help patients with recurrent or severe C. difficile infection.

  NIH research American Gastroenterological Assn/inst · Bethesda, United States · NIH-11394403

• Understanding diet and gut microbiota in eosinophil residency and inflammatory disease

  A physician-scientist-in-training will study how what we eat and our gut microbes influence immune cells in the small intestine, aiming to improve understanding of inflammatory diseases.

  NIH research University of Colorado Denver · Aurora, UNITED STATES · NIH-11393934

• Small intestine microbes and abdominal pain in IBS

  A study from Mayo Clinic aims to understand how tiny microbes in the small intestine contribute to abdominal pain in irritable bowel syndrome and how signals from those microbes reach the nervous system.

  NIH research Mayo Clinic Rochester · Rochester, United States · NIH-11392565

• Gut microbiota and endometriosis: a microbiome-based approach to understanding and treating pain and lesions

  Researchers are studying how the gut microbiome might influence endometriosis to guide new, nonhormonal treatments for symptoms like pelvic pain and infertility.

  NIH research Baylor College of Medicine · Houston, United States · NIH-11391968

• Understanding how HIV PrEP affects gut microbes and inflammation

  A doctor-scientist team will study how HIV prevention pills may change gut viruses and bacteria and whether that relates to gut inflammation in people starting PrEP.

  NIH research Seattle Children's Hospital · Seattle, United States · NIH-11387852

• Orchestrating intestinal immunity through microbiota and CX3CR1+ cells

  This grant explores how gut microbes interact with specific immune cells to support healthy immunity and prevent inflammatory gut problems.

  NIH research Sloan-Kettering Inst Can Research · New York, United States · NIH-11387465

• Nitrate and microbiota balance for better health

  A research project investigates how the mineral nitrate influences the balance of helpful and potentially harmful microbes in areas like the gut and mouth, with hopes of improving health such as blood pressure.

  NIH research Cleveland Clinic Lerner Com-Cwru · Cleveland, United States · NIH-11386637

• Diet, gut bacteria, and inflammation in adults with type 2 diabetes

  A study from Stanford looks at how fermented foods and their molecules in vegetable brine may change gut bacteria and immune responses in adults with type 2 diabetes.

  NIH research Stanford University · Stanford, United States · NIH-11384428

• How breast milk antibodies may steer baby gut bacteria and prevent NEC

  This grant studies how a specific antibody in breast milk (IgA) helps shape a baby’s gut bacteria to prevent a serious intestinal disease called NEC in preterm and term infants.

  NIH research University of Pittsburgh at Pittsburgh · Pittsburgh, United States · NIH-11384391

• Fecal microbiome therapy to help older adults recover after brain injury

  A trial explores giving a healthy gut microbiome to help people, especially older adults, recover better after a traumatic brain injury.

  NIH research University of Vermont & St Agric College · Burlington, United States · NIH-11383110

• HPV, HIV, and mouth bacteria in Nigerian youth

  A study following HIV-exposed and HIV-infected youth to understand how oral HPV infections appear and persist, and how the mouth’s microbes might influence cancer risk.

  NIH research University of Pennsylvania · Philadelphia, United States · NIH-11381961

• Trauma, the gut, and the brain: how gut microbes and microglia affect brain injury

  A study to understand how gut bacteria and brain immune cells interact after a traumatic brain injury and how this might influence recovery.

  NIH research Northwestern University · Chicago, United States · NIH-11381827

• Intratumoral microbiota and immune predictors of response to immunotherapy in lung cancer

  A scientist team will study whether specific microbes inside lung tumors and immune cells can predict who will respond to immunotherapy in lung cancer.

  NIH research Baylor College of Medicine · Houston, United States · NIH-11379074

Related topics

Quick answers

How many Microbiota clinical trials are recruiting right now?

21, as of November 12, 2026. We update this list each time we refresh our data from ClinicalTrials.gov.

Where are these trials running?

In 9 countries. The most sites are in United States (4 trials), France (3 trials), Sweden (3 trials), China (3 trials), Italy (3 trials). Each study page lists its sites and which ones are recruiting.

What phases are they in?

Phase 1/2: 1, Phase 1: 1. Trials with no phase listed are usually device, behavioural or observational studies.

How do I join one?

Open a study, check the "Is this trial a fit for you?" section, then contact the study team listed on the page. They will ask a few screening questions. Asking is free and does not commit you to anything. Talk it over with your doctor first.

Find the studies that fit you

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