NutriDex

The Supplement Research Compendium
🌳

Slippery Elm

Ulmus rubra

Mucilage bark traditionally used to soothe throat and gut irritation.

Preliminary evidence 🛡️Gut & Immune

✚ Updated · How we grade evidence

Evidence tier
Preliminary
Research weight
Citations
6 verified / 6
Classification
Gut & Immune
❝
What the evidence says. Graded preliminary: the demulcent mucilage gives a plausible coating mechanism and lab data show antioxidant activity, but human evidence is limited to small uncontrolled pilots and multi-herb formulas — slippery elm has never been isolated in a proper RCT. (Preliminary evidence: Early or small human trials; promising but not yet conclusive.)

What is Slippery Elm?

Slippery Elm (Ulmus rubra) is a gut and immune supplement used for soothe sore throat & cough. NutriDex grades the human evidence as Preliminary. Slippery elm is the inner bark of the North American red elm. Soaked in water it forms a slick mucilage gel, the basis for its traditional use soothing sore throats, coughs and gut irritation. Human data are thin and indirect. A small open-label pilot (n=31) found a constipation-IBS formula containing slippery elm raised bowel-movement frequency ~20% and cut straining, pain and bloating, while a diarrhoea-IBS formula eased symptoms but not stool frequency. A 16-week uncontrolled study (n=43) of a multi-herb gut formula that included slippery elm reported less reflux, pain and bloating and reduced gut permeability. In vitro, slippery elm scavenged oxygen radicals from inflamed colon biopsies comparably to mesalamine. None of this isolates slippery elm, uses a placebo control, or measures hard endpoints, so benefits remain plausible but unproven. For sore throat and minor cough the rationale is strongest.

Purported Benefits

✓Soothe sore throat & cough
✓Ease IBS symptoms
✓Coat & calm reflux/heartburn
✓Support gut lining

Evidence by outcome

The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.

OutcomeEvidenceEffectStudies
Ease IBS symptomsSingle open-label pilot (n=31) of a multi-herb formula; no placebo control, slippery elm not isolated. Preliminary ↑ benefit 1
Reduce reflux/heartburn & gut permeability16-wk uncontrolled trial (n=43) of a multi-herb formula reduced reflux; cannot attribute effect to slippery elm alone. Preliminary ↑ benefit 1
Soothe sore throat & minor coughPlausible from mucilage rationale and expert opinion, but no controlled human trials measure this endpoint. No Evidence ↑ benefit 1

Dosing & Compounds

Typical Dose
Commonly 0.4–4 g of inner-bark powder taken as a tea, lozenge or in a multi-herb formula, often 3x/day; no validated standardized dose.
Active Compounds
Mucilage (polysaccharide gel)Polyphenol antioxidantsTannins

Safety & Cautions

Generally well tolerated and considered safe; the NIH LiverTox monograph reports no liver-injury signal. Because the mucilage forms a coating gel, it can slow or reduce absorption of oral medicines and other supplements taken at the same time — separate doses by about 2 hours. Allergic reactions are possible, and outer-bark preparations have historically been associated with miscarriage, so it is usually avoided in pregnancy; quality data in pregnancy, breastfeeding and children are lacking. There are no well-documented interactions with anticoagulants, antidiabetics, sedatives or thyroid drugs, but the absorption-delay effect means caution with any narrow-therapeutic-index medication. Educational only — always check with your doctor or pharmacist before combining Slippery Elm with any medicine.

Key Studies

Systematic review Wu 2023 (Nutrients) ✓ Full text
Systematic review of herbal remedies for constipation-IBS excluded the slippery-elm pilot for being small, uncontrolled and open-label; no RCT evidence for the herb alone.
Safety LiverTox 2024 (NIH) ✓ Full text
NIH monograph: slippery elm preparations are generally recognized as safe with no evidence of liver-enzyme elevation or clinically apparent liver injury.
Cohort Ried 2020 ✓ PubMed
16-wk uncontrolled trial (n=43) of a multi-herb formula containing slippery elm: reduced reflux, pain, bloating and intestinal permeability; 40% of PPI users cut reflux meds.
Review Langmead 2002 ✓ PubMed
In vitro: slippery elm scavenged superoxide dose-dependently and reduced oxygen-radical release from inflamed colorectal biopsies, comparably to mesalamine.
Review MSKCC (About Herbs) ✓ Source
Memorial Sloan Kettering: may relieve minor cough or sore throat; no evidence it treats infections, cancer or other serious conditions; human data otherwise lacking.
Cohort Hawrelak 2010 ✓ Full text
Open-label pilot (n=31): constipation-IBS formula with slippery elm raised bowel frequency ~20% (p=0.016) and cut straining, pain and bloating.
6 sources cited · 6 verified Search all studies on PubMed ↗

Common questions about Slippery Elm

What is Slippery Elm used for?

Slippery Elm is most often taken for Soothe sore throat & cough, Ease IBS symptoms, Coat & calm reflux/heartburn, Support gut lining. Mucilage bark traditionally used to soothe throat and gut irritation.

Does Slippery Elm work — what does the evidence say?

Preliminary evidence. Early or small human trials; promising but not yet conclusive. Slippery elm is the inner bark of the North American red elm. Soaked in water it forms a slick mucilage gel, the basis for its traditional use soothing sore throats, coughs and gut irritation. Human data are thin and indirect. A small open-label pilot (n=31) found a constipation-IBS formula containing slippery elm raised bowel-movement frequency ~20% and cut straining, pain and bloating, while a diarrhoea-IBS formula eased symptoms but not stool frequency. A 16-week uncontrolled study (n=43) of a multi-herb gut formula that included slippery elm reported less reflux, pain and bloating and reduced gut permeability. In vitro, slippery elm scavenged oxygen radicals from inflamed colon biopsies comparably to mesalamine. None of this isolates slippery elm, uses a placebo control, or measures hard endpoints, so benefits remain plausible but unproven. For sore throat and minor cough the rationale is strongest.

What is the typical dose of Slippery Elm?

Commonly 0.4–4 g of inner-bark powder taken as a tea, lozenge or in a multi-herb formula, often 3x/day; no validated standardized dose.

Is Slippery Elm safe? Any cautions or side effects?

Generally well tolerated and considered safe; the NIH LiverTox monograph reports no liver-injury signal. Because the mucilage forms a coating gel, it can slow or reduce absorption of oral medicines and other supplements taken at the same time — separate doses by about 2 hours. Allergic reactions are possible, and outer-bark preparations have historically been associated with miscarriage, so it is usually avoided in pregnancy; quality data in pregnancy, breastfeeding and children are lacking. There are no well-documented interactions with anticoagulants, antidiabetics, sedatives or thyroid drugs, but the absorption-delay effect means caution with any narrow-therapeutic-index medication.

How many studies support Slippery Elm?

NutriDex cites 6 sources for Slippery Elm, graded "Preliminary".

Cite this page
APA

Peh, D. (2026). Slippery Elm (Ulmus rubra): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/slippery-elm

BibTeX
@misc{nutridex_slippery_elm,
  author       = {Peh, Daryl},
  title        = {Slippery Elm (Ulmus rubra): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/slippery-elm},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

← Back to the full dex · All substances