An observational study in Alcoholic Intoxication and Alcohol-Related Disorders, sponsored by National Institutes of Health Clinical Center (CC). Completed at 1 site in United States. Open to participants aged 18 Years to 99 Years. Per ClinicalTrials.gov, last updated 2026-10-16.
Sponsored by National Institutes of Health Clinical Center (CC) · Observational
Background:
Many bacteria live in the gut. The gut is the tube that moves food from the mouth through the stomach to the intestines. Heavy alcohol use disturbs these bacteria. There is evidence that the bacteria in the gut may affect anxiety and depression. Researchers want to learn more about these bacteria in order to better treat diseases such as alcohol dependence.
Objective:
To identify the different bacteria that live in the mouth and gut. Also, to learn if these bacteria change as a person goes through alcohol detoxification.
Eligibility:
People ages 18 and older who:
Design:
Participants will have physical exams.
Participants will answer questions about:
Participants will keep a regular record of their diet.
Participants will have breath alcohol analysis 4 times per day.
Participants will provide stool and oral specimens at most once a day for the first week. Then, they will provide them once a week while they are at the Clinical Center.
Participants will have a dental visit. This consists of an oral exam and oral health assessment. The dentist may recommend a cleaning or dental X-rays.
The microbiome exists in a complex symbiotic relationship with its human host, the characterization of which is imperative for understanding a myriad of diseases. Until recently, much of gut microbiome research has focused on gastrointestinal disorders. Recent research, however, has implicated the gut microbiome in psychological disorders as well through a proposed gut-brain axis. Of particular interest is characterization of the microbiome of individuals with severe alcohol use disorders, as alcohol has been known to profoundly alter the gut microbiome. For many years, scientists have theorized a connection between the proinflammatory mediators produced by ethanol consumption, liver disease and the gut microbiome. This study represents the first instance in which the naturalistic time course of changes in the gut microbiome will be followed in alcoholics in whom detailed history of alcohol consumption and diet have been obtained. We hypothesize that the gut microbiome will renormalize spontaneously and without specific intervention over a time frame of one or two weeks. Alcoholic patients also suffer from serious oral hygiene problems associated with alterations in oral microbial flora. We hypothesize that abnormalities in the oral microbiome will be detectable on admission, and that these will also rapidly renormalize with abstinence and resumption of ordinary diet and oral hygiene. If not, the findings in this study could point to the need for other interventions, such as administration of probiotics. Twenty evaluable participants admitted to the Clinical Center for alcohol detoxification will be enrolled. All patients will be admitted under the Unit and Clinic Evaluation, Screening, Assessment, and Management protocol (14-AA-0181), which includes adults 18 years of age or older seeking treatment for severe alcohol use disorders. Oral (tongue brushings) and gut (stool) specimens will be collected daily for the first week and then once a week for 28 days. Demographic characteristics, detailed drinking and dietary histories, measures of addiction severity, comorbid mental disorders, and metabolic indicators of other disease will be collected for correlation with microbiological results. Dietary records will include use of probiotics. Exclusion criteria include use of antibiotics, corticosteroids or immunosuppressive agents within the past month. Informed consent will be obtained after consent for the screening and treatment protocol (14-AA-0181) and in accordance with policies protecting participants with impaired decision-making. Microbial identification will include 16S rRNA analysis and a validated Next Generation Sequencing analysis pipelines. Statistical comparisons between each patient's oral and gut microbiome samples will be evaluated and all results from this population will also be compared to published microbiomes in both healthy volunteers as well as existing data from alcohol dependent individuals. Participants will be compensated for research-related discomfort and inconveniences in accordance with NIH guidelines.
76 studies on the registry are indexed under Alcoholic Intoxication; 17 are open to participants now.
This study's enrollment of 23 is below the median of 240 across 11 observational studies indexed under Alcoholic Intoxication.
Browse Alcoholic Intoxication studies →National Institutes of Health Clinical Center (CC) is the lead sponsor of 375 studies on the registry; 27 are open to participants now.
Of its 23 completed or terminated interventional studies of FDA-regulated products, 19 (83%) have results posted.
Counted across the registry records on this site, refreshed daily.
inpatient treatment seeking alcohol dependent participants
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
EXCLUSION CRITERIA:
Currently using or have used any of the following drugs within the last month by self-report:
Some of these exclusionary criteria have been adapted from the Human Microbiome Project [40]. All exclusion measures will be collected from self-report.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The participants/group were treatment-seeking AUD individuals admitted to the NIH CC 1SE Addictions Unit.
Identification of bacteria in the gut and oral microbiomes over time
Characterization of the gut and oral micro biome
Time frame: all timepoints
Plan to share: Undecided
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is completed, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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