Slippery elm is the mucilage-rich inner bark of Ulmus rubra, an exogenous botanical material studied mainly in oral demulcent contexts and multi-ingredient digestive formulas rather than as a well-characterized standalone extract. (NIH/NCBI) (Research)
Slippery elm has a Limited / Mixed human evidence base because most human studies evaluate formulas that contain slippery elm rather than slippery elm alone. The clearest single-ingredient exposure is powdered dried bark in throat lozenges, while digestive and IBS studies generally use multi-ingredient formulas that do not isolate slippery elm’s independent effect. (Health Canada) (Research) No direct human clinical evidence was collected for slippery elm in vaginal dryness, vaginal moisture, vaginal lubrication, vulvovaginal atrophy, or genitourinary syndrome of menopause.
Ingredient Identity
- Official name(s): Slippery elm; Ulmus rubra inner bark. (NIH/NCBI)
- Synonyms: Red elm, Indian elm, moose elm, and Ulmus fulva in older naming contexts. (NIH/NCBI)
- Classification: Botanical inner bark; mucilage-rich demulcent material. (FDA)
- CAS number: Not applicable as a single defined CAS number for whole slippery elm inner bark.
- Endogenous vs exogenous: Exogenous botanical material; it is not produced in the human body. (NIH/NCBI)
Ingredient Snapshot
- Classification: Mucilage-rich botanical bark used in demulcent oral-health contexts. (FDA)
- Endogenous vs exogenous status: Exogenous plant-derived material. (NIH/NCBI)
- Primary human research domains: Oral Health, Digestive and Gastrointestinal Health, Beauty and Skin Health, Women’s Health evidence-limit clarification, and Cancer Research context through multi-ingredient formulas. (Research) (Research) (NCI)
- Common study formats: Multi-ingredient formulas, one randomized sore-throat tea study, open-label digestive studies, case reports, and ex vivo human-tissue research. (Research) (Research)
- Pharmacokinetic characterization status: Human Tmax, half-life, systemic absorption, and standardized extract pharmacokinetics were not identified in the collected evidence.
- Regulatory context: FDA includes elm bark in an oral-demulcent context, and Health Canada lists powdered slippery elm bark in throat-lozenge monograph dosing. (FDA) (Health Canada)
- Evidence maturity: Limited / Mixed because most human evidence is formula-level rather than slippery-elm-only. (Research)
Introduction
Slippery elm is derived from the inner bark of Ulmus rubra, a North American elm species. Its scientific and regulatory relevance centers on mucilage-rich bark material, especially in oral demulcent and throat-lozenge contexts. (NIH/NCBI) (FDA)
People commonly search slippery elm for sore throat, reflux-like symptoms, IBS, constipation, gut coating, extracts, medication interactions, skin conditions, and vaginal moisture. The collected human research mainly evaluates slippery elm inside multi-ingredient products, including a sore-throat tea, IBS formulas, digestive formulas, psoriasis nutrition protocols, and Essiac-type formulas. (Research) (Research) (NCI)
This article is informational only, describes slippery elm as a botanical substance studied in human research, and does not provide medical or dosing advice.
Quick Summary
- Slippery elm is the inner bark of Ulmus rubra, a mucilage-rich botanical material used in oral demulcent contexts. (NIH/NCBI) (FDA)
- The clearest single-ingredient exposure in the collected evidence is 200–300 mg powdered dried bark per lozenge, with a Health Canada monograph maximum of 6 g/day in that lozenge context. (Health Canada)
- Digestive and IBS evidence is mostly formula-level because the studies combined slippery elm with other ingredients, including lactulose, oat bran, licorice root, curcumin, aloe vera, guar gum, pectin, peppermint oil, and glutamine. (Research) (Research)
- Extract evidence is not well characterized in humans; the collected extract-relevant study is ex vivo human-tissue research, not an oral human extract trial. (Research)
- No direct human clinical evidence was collected for slippery elm in vaginal dryness, vaginal moisture, vaginal lubrication, vulvovaginal atrophy, or genitourinary syndrome of menopause.
- Cancer-related discussion should be limited to Essiac and Flor Essence context because those are multi-herb formulas that include slippery elm, not slippery-elm-only interventions. (NCI)
- LiverTox reports no published liver-injury cases attributed to slippery elm, while also indicating that large clinical safety datasets are limited. (NIH/NCBI)
Human Research Findings by Condition
Oral Health
Human research in Oral Health includes a randomized trial of Throat Coat, a multi-herb demulcent tea containing elm inner bark, for acute pharyngitis symptoms. This supports formula-level sore-throat evidence, not a slippery-elm-only conclusion. (Research)
Key human study
Dose studied: Multi-herb tea exposure; slippery elm amount not isolated.
Population: Patients with acute pharyngitis.
Duration: Short-term symptom assessment.
Researchers studied Throat Coat for temporary relief of sore-throat pain in acute pharyngitis. The study is relevant to slippery elm because the tea contained elm inner bark, but the intervention included multiple herbs, so the result cannot be assigned to slippery elm alone. (Research)
Result: Randomized human trial reported a statistically significant improvement
Evidence strength: Limited
Study source: (Research)
Digestive and Gastrointestinal Health
Digestive and Gastrointestinal Health is the largest human research area in the collected slippery elm evidence. The evidence remains limited because studies used multi-ingredient formulas rather than slippery elm as a standalone intervention. (Research) (Research)
Key human study
Dose studied: Formula exposure; individual slippery elm dose not isolated.
Population: 31 adults meeting Rome II criteria for IBS.
Duration: Pilot treatment study.
The IBS pilot study tested two natural medicine formulas containing dried powdered slippery elm bark. The constipation-predominant formula also contained lactulose, oat bran, and licorice root, which prevents attribution to slippery elm alone. (Research)
Result: Human clinical study reported a modest improvement
Evidence strength: Limited
Study source: (Research)
Additional human study
Dose studied: 5 g/day and 10 g/day total formula, not slippery elm alone.
Population: Adults with digestive disorders.
Duration: 16 weeks.
The NC Gut Relief Formula study evaluated a product containing curcumin, aloe vera, slippery elm, guar gum, pectin, peppermint oil, and glutamine. Reported digestive outcomes apply to the full formula, not to isolated slippery elm. (Research)
Result: Human clinical study reported a modest improvement
Evidence strength: Limited
Study source: (Research)
Beauty and Skin Health
Human evidence in Beauty and Skin Health is limited to case-report-level evidence from a multi-component psoriasis nutrition protocol. The protocol included slippery elm bark water, but it also included other dietary changes and components, so the findings cannot isolate slippery elm. (Research)
Key human study
Dose studied: Daily slippery elm bark water; amount not specified.
Population: Five adults with chronic plaque psoriasis.
Duration: Six-month follow-up.
The psoriasis case-report series included slippery elm bark water within a broader medical nutrition protocol. This evidence is exploratory and cannot isolate slippery elm’s independent role. (Research)
Result: Human evidence remains limited or inconclusive
Evidence strength: Emerging
Study source: (Research)
Cancer Research
Cancer Research evidence is limited to Essiac and Flor Essence contexts, where slippery elm appears as one component of multi-herb formulas. NCI describes Essiac and Flor Essence as multi-herb products, so they should not be used as evidence that slippery elm itself has cancer-treatment effects. (NCI)
Key human study
Dose studied: Essiac formula exposure; slippery elm dose not isolated.
Population: Women with breast cancer.
Duration: Not used for slippery-elm dosing interpretation.
A human Essiac study is relevant only as formula-context evidence. It does not establish slippery-elm-specific effects because Essiac contains multiple herbs. (Research) (NCI)
Result: Human clinical study reported no clear effect
Evidence strength: Limited
Study source: (Research)
Women’s Health
No direct human clinical study was collected for slippery elm in vaginal dryness, vaginal moisture, vaginal lubrication, vulvovaginal atrophy, or genitourinary syndrome of menopause. This topic should still be addressed because readers search for it, but the evidence position should be stated as unsupported by direct slippery-elm clinical research.
Key human study
Dose studied: No verified slippery-elm dose studied for vaginal dryness or vaginal moisture.
Population: No direct slippery-elm human study population identified.
Duration: Not applicable.
The collected evidence does not support a clinical claim that slippery elm improves vaginal dryness, vaginal moisture, or vaginal lubrication. Mucilage-based demulcent plausibility should not be treated as evidence for vaginal tissue or vaginal symptoms.
Result: Human evidence remains limited or inconclusive
Evidence strength: Inconclusive
Study source: No direct human slippery-elm source was collected for this claim.
Dosage & Study Snapshot (Research Context)
Human exposure evidence should be separated into single-ingredient powdered bark exposure, multi-ingredient formula exposure, and nonclinical or ex vivo extract-related evidence. Powdered bark, bark water, tea/infusion, standardized extract, and multi-ingredient formulas are not interchangeable.
Slippery-Elm-Specific Exposure
200–300 mg powdered dried slippery elm bark per lozenge:
Health Canada lists slippery elm powder in throat lozenges at 200–300 mg per lozenge. This is the clearest single-ingredient exposure in the collected evidence. The material is powdered bark in a lozenge context, not a standardized extract, tincture, digestive formula, or loose-powder dose. (Health Canada)
Result: Preliminary signal
Evidence strength: Limited
Notes / limitations: This is monograph-based lozenge context, not a standalone clinical efficacy trial.
Up to 6 g/day powdered dried slippery elm bark in lozenge context:
Health Canada lists a maximum of 6 g/day for powdered slippery elm bark in throat lozenges. This value should not be generalized to capsules, loose powders, teas, tinctures, extracts, or digestive formulas. (Health Canada)
Result: Preliminary signal
Evidence strength: Limited
Notes / limitations: The maximum applies to the specified lozenge context.
Daily slippery elm bark water, amount not specified:
The psoriasis case series reported daily slippery elm bark water as part of a multi-component nutrition protocol. The amount of slippery elm bark was not specified in the collected evidence. This should be described as a bark-water or mucilage-style exposure, not as a quantified dose band. (Research)
Result: Inconclusive
Evidence strength: Emerging
Notes / limitations: The protocol included multiple components and cannot isolate slippery elm.
Multi-Ingredient Formula Exposure
Throat Coat tea exposure containing elm inner bark:
The acute pharyngitis trial studied a multi-herb tea containing elm inner bark. This exposure is relevant for formula-level oral demulcent research, but it should not be converted into a slippery-elm-only dose. (Research)
Result: Statistically significant improvement
Evidence strength: Limited
Notes / limitations: The intervention was multi-herb and does not isolate slippery elm.
IBS formulas containing dried powdered slippery elm bark:
The IBS pilot study used two formulas containing dried powdered slippery elm bark. The study supports formula-level digestive research, but the individual slippery elm dose and independent contribution were not isolated. (Research)
Result: Modest improvement
Evidence strength: Limited
Notes / limitations: The findings apply to formulas, not slippery elm alone.
5 g/day and 10 g/day total NC Gut Relief Formula:
The NC Gut Relief study used 5 g/day and then 10 g/day of the complete formula. The formula contained slippery elm with curcumin, aloe vera, guar gum, pectin, peppermint oil, and glutamine, so these values are total formula doses. (Research)
Result: Modest improvement
Evidence strength: Limited
Notes / limitations: The dose refers to the whole formula, not slippery elm.
Extract Evidence Not Used for Human Dose Bands
No standardized Ulmus rubra extract human dose identified:
No standalone human clinical dose study of standardized Ulmus rubra extract was collected. The extract-relevant source in this evidence set is an ex vivo human-tissue study involving herbs including slippery elm, which does not establish oral extract dosing, absorption, or clinical outcomes. (Research)
Result: Inconclusive
Evidence strength: Emerging
Notes / limitations: Ex vivo human-tissue evidence is not the same as an oral human clinical trial.
Key Takeaways from Human Research
- Human evidence for slippery elm is limited and mostly formula-level rather than slippery-elm-only. (Research) (Research)
- The clearest single-ingredient exposure is powdered dried bark in lozenges, not standardized extract. (Health Canada)
- Digestive findings should be interpreted cautiously because IBS and GI studies combined slippery elm with other ingredients. (Research)
- Extract-related evidence should not be presented as human oral extract evidence because the collected study is ex vivo human-tissue research. (Research)
- No direct human clinical evidence was collected for vaginal dryness, vaginal moisture, vaginal lubrication, vulvovaginal atrophy, or genitourinary syndrome of menopause.
- LiverTox reports no published liver-injury cases attributed to slippery elm. (NIH/NCBI)
Origin & Natural Occurrence
Slippery elm is derived from the inner bark of Ulmus rubra. LiverTox describes slippery elm as a bark-derived botanical preparation used orally in traditional and supplement contexts. (NIH/NCBI)
Slippery elm is not a human endogenous compound or a common dietary nutrient. The collected evidence concerns bark preparations and formulas rather than ordinary dietary intake. (NIH/NCBI)
How It Behaves in the Body
The main plain-language concept for slippery elm is mucilage, a plant material that can form a slippery texture when hydrated. FDA’s oral-demulcent context for elm bark supports local soothing use in oral healthcare, but it does not establish systemic pharmacologic effects. (FDA)
Human pharmacokinetic data were not collected for slippery elm. No verified human Tmax, half-life, standardized extract absorption, or systemic exposure study was included in the evidence set.
Mechanistic evidence includes an ex vivo study in which herbal remedies including slippery elm were tested in cell-free systems and inflamed human colorectal biopsies. This supports laboratory-level plausibility for antioxidant activity in a tissue model, but it does not prove clinical effects after oral use. (Research)
Absorption & Delivery Formats
Oral immediate-release: Powdered bark lozenges, teas, bark water, and digestive formulas are the main oral formats in the collected evidence. The clearest single-ingredient exposure is powdered bark in lozenges, while the clinical digestive studies are formula-level. (Health Canada) (Research)
Oral extended-release: No oral extended-release slippery elm human study was collected.
Sublingual: No sublingual slippery elm human study was collected.
Transdermal: No transdermal slippery elm human study was collected.
Injectable / IV: No injectable or IV slippery elm human study was collected.
Extract formats: No standalone human clinical study of standardized Ulmus rubra extract was collected. Extract discussion should remain limited to ex vivo context unless additional evidence is added. (Research)
Quick Facts at a Glance
Onset (reported): The collected onset-relevant evidence comes from a multi-herb sore-throat tea study, not slippery elm alone. It should be described only as formula-level short-term evidence. (Research)
Time to peak (Tmax): No human Tmax data for slippery elm were collected. The evidence set does not characterize slippery elm like a systemically absorbed drug.
Half-life (t½): No human half-life data were collected. Whole bark mucilage is not pharmacokinetically characterized in the collected evidence.
Typical duration: Human digestive studies included pilot IBS research and a 16-week NC Gut Relief Formula study, but those durations apply to formulas rather than slippery elm alone. (Research) (Research)
Absorption routes studied: Oral exposure was the only human-use route represented in the collected evidence. Ex vivo biopsy work does not represent an absorption route in humans. (Research)
Formulation differences: Powdered bark lozenges, tea formulas, bark water, digestive formulas, and extract-related tissue exposure should be treated separately. Formula studies do not define a slippery-elm-only dose. (Research)
Variability drivers: Interpretation varies by whether the source is powdered bark, bark water, tea, formula, or ex vivo extract-related exposure. The largest limitation is that several studies do not isolate slippery elm’s dose or effect. (Research)
Tolerance / adaptation: No direct tolerance or adaptation study for standalone slippery elm was collected. Formula studies reported tolerability, but this does not establish slippery-elm-specific adaptation. (Research)
Evidence strength snapshot: Overall evidence is Limited / Mixed because the collected human research is small and mostly formula-level. (Research) (NIH/NCBI)
Safety, Interactions & Regulation
LiverTox reports no published case reports of liver injury attributed to slippery elm. This should be interpreted cautiously because large clinical safety datasets are limited. (NIH/NCBI)
The IBS pilot study reported that the formulas containing slippery elm were well tolerated. That tolerability finding applies to the formulas rather than to slippery elm alone. (Research)
The NC Gut Relief Formula study assessed tolerability and digestive outcomes in a formula containing slippery elm. The study cannot isolate slippery-elm-specific adverse effects because the intervention contained multiple ingredients. (Research)
Direct human medication-interaction trials for slippery elm were not collected. Because slippery elm is mucilage-rich and used in demulcent contexts, medication-absorption concerns should be framed cautiously as theoretical unless supported by direct interaction research. (FDA)
In the United States, FDA’s OTC oral healthcare monograph includes elm bark in an oral-demulcent context. This does not mean slippery elm is FDA-approved for IBS, GERD, vaginal dryness, psoriasis, cancer, or systemic disease treatment. (FDA)
Health Canada lists powdered slippery elm bark in throat lozenges at 200–300 mg per lozenge, up to 6 g/day, in a specific lozenge-context monograph. (Health Canada)
EMA describes the EU herbal-monograph framework, but no Ulmus rubra-specific EMA monograph was included in the collected evidence. (EMA)
Evidence Overview
The overall evidence base for slippery elm is Limited / Mixed. The most reliable single-ingredient information concerns powdered dried bark in lozenge form, while most human clinical evidence comes from multi-ingredient formulas for Oral Health or Digestive and Gastrointestinal Health. This distinction is central to interpreting slippery elm because formula studies can show what happened with a complete product, but they cannot prove the independent effect of slippery elm. (Health Canada) (Research)
The strongest human research areas are sore-throat formula evidence and digestive formula evidence. The Throat Coat study tested a multi-herb tea for acute pharyngitis, while the IBS and NC Gut Relief studies tested formulas that included slippery elm with other ingredients. These studies are useful for documenting where slippery elm appears in human research, but they should not be summarized as slippery-elm-only efficacy trials. (Research) (Research)
Evidence is much weaker for Beauty and Skin Health, Women’s Health, Cancer Research, and extract-specific claims. Psoriasis evidence comes from a small case-report series using a multi-component nutrition protocol, Women’s Health claims for vaginal dryness lack direct slippery-elm clinical evidence, and Cancer Research discussion should be limited to Essiac/Flor Essence context. (Research) (NCI)
Confidence is limited because the literature rarely isolates slippery elm as the only intervention. Future research would need clearly defined slippery elm preparations, transparent dose reporting, standardized extract characterization if extracts are studied, and direct measurement of local-contact or pharmacokinetic endpoints.
Evidence Confidence Classification
Limited / Mixed is the appropriate overall evidence classification for slippery elm because the collected human evidence is small, mostly formula-level, and rarely isolates slippery elm as a standalone ingredient. (Research) (Research)
The strongest evidence is not for broad health effects, but for defined contexts: powdered bark lozenge monograph use and multi-ingredient formulas studied in Oral Health and Digestive and Gastrointestinal Health. (Health Canada) (Research)
Evidence is especially limited for standardized Ulmus rubra extract dosing, vaginal dryness or vaginal moisture, standalone pharmacokinetics, and slippery-elm-only digestive outcomes. (Research)
Similar Ingredients & Comparators
Similar supplement-style ingredients:
- Marshmallow root
- Licorice root
- Aloe vera
- Pectin
- Guar gum
- Oat bran
- Peppermint oil
- Psyllium husk
- Demulcent herbal teas
- Other mucilage-rich botanicals
Medical / pharma comparator categories:
- Oral demulcents
- Throat lozenges
- Bulk-forming fibers
- Osmotic laxatives
- Acid-reflux medications
- Nonhormonal vaginal moisturizers
- Topical psoriasis therapies
Combination Context
Slippery Elm + Lactulose + Oat Bran + Licorice Root:
This combination appeared in the constipation-predominant IBS formula studied in the open-label pilot trial. The formula reported symptom changes, but the study does not isolate slippery elm from the other ingredients. (Research)
Slippery Elm + Curcumin + Aloe Vera + Guar Gum + Pectin + Peppermint Oil + Glutamine:
This combination was studied as NC Gut Relief Formula in adults with digestive disorders. The 5 g/day and 10 g/day exposures refer to the whole formula, not slippery elm alone. (Research)
Slippery Elm + Essiac / Flor Essence Herbs:
Slippery elm appears in Essiac and Flor Essence formulas discussed by NCI. These formulas should not be used as evidence that slippery elm treats cancer. (NCI)
Slippery Elm + Saffron Tea in Nutrition Protocol:
A psoriasis case-report series included slippery elm bark water and saffron tea within a broader medical nutrition protocol. The evidence is exploratory and cannot isolate slippery elm. (Research)
FAQ
What is slippery elm?
Slippery elm is the inner bark of Ulmus rubra, a mucilage-rich North American elm bark material. It appears in evidence and regulatory contexts mainly as powdered bark, elm bark demulcent material, or one ingredient in multi-ingredient formulas. (NIH/NCBI) (FDA)
What is slippery elm mainly studied for in humans?
Human research mainly studies slippery elm in multi-ingredient formulas for sore throat, IBS, and broader digestive symptoms. The available studies generally do not isolate slippery elm as the only active ingredient, so their findings should be interpreted as formula-level evidence. (Research) (Research) (Research)
Does slippery elm help with sore throat?
A randomized human trial studied Throat Coat, a multi-herb tea containing elm inner bark, for temporary sore-throat pain relief in acute pharyngitis. The trial supports formula-level evidence for that tea, not proof that slippery elm alone produces the same effect. (Research)
Does slippery elm help with acid reflux or GERD?
Direct slippery-elm-only human trials for acid reflux or GERD were not collected. The strongest related digestive evidence comes from multi-ingredient digestive formulas that included slippery elm, so reflux or GERD claims should be described as indirect or formula-level. (Research)
Does slippery elm help with IBS?
Slippery elm has been studied in IBS as part of multi-ingredient formulas. One open-label pilot study tested formulas containing dried powdered slippery elm bark and reported IBS symptom changes, but it did not isolate slippery elm’s independent contribution. (Research)
Does slippery elm help with constipation?
Constipation-related evidence comes from a constipation-predominant IBS formula that contained dried powdered slippery elm bark, lactulose, oat bran, and licorice root. Because the formula contained multiple ingredients, the evidence does not show whether slippery elm alone affected bowel movements or stool consistency. (Research)
Does slippery elm coat the stomach or gut?
Slippery elm is commonly described as mucilage-rich, meaning it contains plant material that can form a slippery texture when hydrated. FDA’s oral-demulcent context supports local soothing use for elm bark in oral healthcare, but the collected evidence does not directly measure a coating effect inside the human stomach or intestines. (FDA)
Is slippery elm good for gut inflammation?
The collected evidence includes an ex vivo human-tissue study that tested herbs including slippery elm in inflamed colorectal biopsy samples from ulcerative-colitis patients. That study is laboratory-based and should not be interpreted as evidence that oral slippery elm reduces gut inflammation in patients. (Research)
Does slippery elm help with ulcers or gastritis?
No direct human clinical trial of slippery elm alone for stomach ulcers or gastritis was collected. Claims about ulcers or gastritis should therefore be treated as unsupported by direct slippery-elm clinical evidence unless a verified trial is added.
Does slippery elm help with vaginal dryness or vaginal moisture?
No direct human clinical trial was collected for slippery elm in vaginal dryness, vaginal moisture, vaginal lubrication, vulvovaginal atrophy, or genitourinary syndrome of menopause. Slippery elm’s mucilage-rich demulcent reputation does not establish clinical evidence for vaginal tissue or vaginal symptoms.
Does slippery elm increase female lubrication?
No direct human evidence was collected showing that slippery elm increases vaginal lubrication. This claim should be treated as unsupported by direct slippery-elm research.
Does slippery elm affect hormones or estrogen?
No human evidence was collected showing that slippery elm changes estrogen, progesterone, testosterone, or other hormone levels. Hormonal or estrogen-related claims should not be made without direct human evidence.
Does slippery elm help with skin or psoriasis?
Only weak human evidence was collected for skin-related use. A five-person psoriasis case-report series included slippery elm bark water as part of a broader nutrition protocol, but the protocol had multiple components and cannot isolate slippery elm’s effect. (Research)
Does slippery elm help with cancer?
No slippery-elm-specific human evidence was collected showing cancer-treatment effects. NCI discusses slippery elm as one ingredient in Essiac and Flor Essence formulas, and those formulas should not be treated as evidence that slippery elm treats cancer. (NCI)
Is slippery elm a powder, bark, tea, or extract?
The clearest single-ingredient evidence source identifies slippery elm as powdered dried bark in throat lozenges. Human studies also used tea formulas, bark water, and multi-ingredient digestive formulas, but no standalone human clinical study of standardized Ulmus rubra extract was collected. (Health Canada) (Research)
What dose of slippery elm has been studied?
The clearest slippery-elm-specific exposure is 200–300 mg powdered dried bark per lozenge, with a Health Canada maximum of 6 g/day in that lozenge context. Digestive studies used formula-level exposures, including 5 g/day and 10 g/day of a complete multi-ingredient formula. (Health Canada) (Research)
Is 5 g or 10 g a slippery elm dose?
No. In the NC Gut Relief Formula study, 5 g/day and 10 g/day referred to the total multi-ingredient formula, not to slippery elm alone. (Research)
Is there research on slippery elm extract?
No standalone human clinical study of standardized Ulmus rubra extract was collected. The extract-relevant evidence in the source set is ex vivo human-tissue research, which cannot establish oral extract dosing, absorption, or clinical outcomes. (Research)
How quickly does slippery elm work?
The collected evidence does not define onset for standalone slippery elm. The sore-throat trial measured short-term effects of a multi-herb tea containing elm inner bark, so onset should be described only for that formula context. (Research)
How long does slippery elm stay in the body?
No human pharmacokinetic study was collected that reports slippery elm half-life, Tmax, systemic absorption, or duration in the body. The evidence base is mainly local demulcent context, formula studies, and ex vivo tissue work.
Can slippery elm affect medication absorption?
Direct human medication-interaction trials for slippery elm were not collected. Because slippery elm is mucilage-rich and used as a demulcent, medication-absorption concerns should be framed cautiously as theoretical unless supported by direct interaction evidence. (FDA)
Is slippery elm safe?
LiverTox reports no published cases of liver injury attributed to slippery elm. Formula studies reported tolerability findings, but those results apply to the full formulas rather than to slippery elm alone. (NIH/NCBI) (Research)
Is slippery elm FDA-approved?
FDA includes elm bark in an OTC oral-healthcare demulcent monograph context. This should not be interpreted as FDA approval of slippery elm for IBS, GERD, vaginal dryness, psoriasis, cancer, or systemic disease claims. (FDA)
How is slippery elm regulated outside the United States?
Health Canada lists powdered slippery elm bark in throat lozenges at 200–300 mg per lozenge and up to 6 g/day in that context. EMA provides a general framework for EU herbal monographs, but no Ulmus rubra-specific EMA monograph was included in the collected evidence set. (Health Canada) (EMA)
Resources
- LiverTox: Slippery Elm — NIH/NCBI — https://www.ncbi.nlm.nih.gov/books/NBK599741/
- Health Canada Throat Lozenges Monograph — Health Canada — https://webprod.hc-sc.gc.ca/nhpid-bdipsn/atReq?atid=throat.lozenges.pastilles2&lang=eng
- FDA OTC Oral Healthcare Products Monograph — FDA — https://www.accessdata.fda.gov/drugsatfda_docs/omuf/monographs/OTC%20Monograph_M022-Oral%20Healthcare%20Products%20for%20OTC%20human%20Use%2010.14.2022.pdf
- Throat Coat Acute Pharyngitis Trial — PubMed — https://pubmed.ncbi.nlm.nih.gov/12804082/
- IBS Natural Medicine Formulas Study — PubMed — https://pubmed.ncbi.nlm.nih.gov/20954962/
- NC Gut Relief Formula Study — PubMed — https://pubmed.ncbi.nlm.nih.gov/32151878/
- Ulcerative-Colitis Biopsy Antioxidant Study — PubMed — https://pubmed.ncbi.nlm.nih.gov/11860402/
- Psoriasis Nutrition Protocol Case Reports — PubMed — https://pubmed.ncbi.nlm.nih.gov/15387720/
- NCI Essiac / Flor Essence PDQ — NCI — https://www.cancer.gov/about-cancer/treatment/cam/hp/essiac-pdq
- EMA EU Herbal Monograph Framework — EMA — https://www.ema.europa.eu/en/human-regulatory-overview/herbal-medicinal-products/european-union-monographs-list-entries
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