Supplements · September 29, 2026 · Memios · 6 min read
Slippery elm
Not enough research to say. It is used to soothe sore throats and the gut.
TLDR
- Not enough research to say. It is used to soothe sore throats and the gut.
- What it is: The powdered inner bark of the slippery elm tree, native to eastern North America. The bark is rich in mucilage, a mix of carbohydrates that swells into a thick gel in water.
- Main use, supported: In the same uncontrolled pilot, a formula of slippery elm, lactulose, oat bran and licorice improved bowel habit and symptoms in constipation-type IBS. (very low certainty)
- Claim NOT supported by research: In a small pilot study, slippery elm drinkers tended to rate throat soothing higher than tea drinkers, but the difference was not statistically significant. (very low certainty)
- Another claim NOT supported: An open-label, uncontrolled pilot found a slippery-elm-containing formula did not improve bowel habit in diarrhoea-type or alternating IBS. (very low certainty)
- Recommended dose: not established. There is no RDA or AI: slippery elm is an herbal product, not a nutrient. No reference intake was found.
- Studied dose (a trial dose, not a recommendation): Dried powdered slippery elm bark was given as part of two multi-ingredient IBS formulas (with bilberry, agrimony and cinnamon, or with lactulose, oat bran and licorice). Findings citing that trial: 1 for, 1 against.
- Upper limit: No upper limit has been set.
- What goes wrong: 2 findings on harm. Slippery elm has been reported to have abortive effects, and a review says it is not recommended in pregnancy.
- Common myth: Slippery elm is proven to soothe the throat and heal the gut.
What it is
The powdered inner bark of the slippery elm tree, native to eastern North America. The bark is rich in mucilage, a mix of carbohydrates that swells into a thick gel in water.
What the research says
It is used to soothe sore throats and the gut. No properly controlled trial of slippery elm alone was found. A small pilot study found soothing ratings were not significantly better than with ordinary tea. An uncontrolled IBS study tested multi-ingredient formulas, so the effect of slippery elm alone cannot be separated out. There are reports of abortive effects, so pregnancy is a warning. Elm oleoresins can cause contact dermatitis and elm pollen is an allergen. No side-effect rates have been published.
Evidence grade: Not enough research to say.
What goes wrong
Slippery elm has been reported to have abortive effects, and a review says it is not recommended in pregnancy. (Source 1)
- Official position, Very low certainty.
- Size: not stated.
- Who: pregnant women.
- How long: not applicable.
- Result: No rates; based on reports, not trials.
- Funding: not stated.
It has been reported that slippery elm has abortive effects, and its use by females who are pregnant is not recommended.
Oleoresins from several elm species have been reported to cause contact dermatitis, and slippery elm pollen is a known allergen. (Source 2)
- Official position, Very low certainty.
- Size: not stated.
- Who: people exposed to elm oleoresin or pollen.
- How long: not applicable.
- Result: No rates reported.
- Funding: commercial drug-information publisher.
Oleoresins from several Ulmus species have been reported to cause contact dermatitis, and the pollen of slippery elm is a known allergen.
What the evidence supports
In the same uncontrolled pilot, a formula of slippery elm, lactulose, oat bran and licorice improved bowel habit and symptoms in constipation-type IBS. (Source 3)
- Case series, Very low certainty.
- Size: 10 patients (C-IBS arm)
- Who: adults with constipation-predominant IBS.
- How long: not stated in abstract.
- Result: 20% increase in bowel movement frequency (p = 0.016); global IBS symptom severity reduced (p = 0.0005). No control group; multi-ingredient.
- Funding: not stated.
This was a two arm, open-label, uncontrolled pilot study.
What the evidence does not support
A reference monograph states that no large clinical studies exist and data are lacking for any use of slippery elm. (Source 2)
- Official position, Certainty not rated.
- Size: not applicable.
- Who: not applicable.
- How long: not applicable.
- Result: No large clinical studies identified.
- Funding: commercial drug-information publisher.
no large clinical studies exist, and data are lacking to support use of slippery elm for any indication.
In a small pilot study, slippery elm drinkers tended to rate throat soothing higher than tea drinkers, but the difference was not statistically significant. (Source 1)
- Case series, Very low certainty.
- Size: small pilot sample (number not in fetched text)
- Who: pilot study participants.
- How long: single dose, ratings at 1 to 10 minutes.
- Result: Trend favouring slippery elm over Lipton tea; not statistically significant; authors say study was underpowered.
- Funding: not stated.
the difference did not reach the level of statistical significance
An open-label, uncontrolled pilot found a slippery-elm-containing formula did not improve bowel habit in diarrhoea-type or alternating IBS. (Source 3)
- Case series, Very low certainty.
- Size: 21 patients (DA-IBS arm) of 31.
- Who: adults meeting Rome II criteria for diarrhoea-predominant or alternating IBS, Australia.
- How long: not stated in abstract.
- Result: Small increase in bowel movement frequency (p = 0.027) with no improvement in bowel habit; some symptom scores fell. Formula also contained bilberry, agrimony and cinnamon.
- Funding: not stated.
The DA-IBS formula was not effective in improving bowel habit in individuals with diarrhea-predominant or alternating bowel habit IBS
Where the research disagrees
Whether slippery elm helps IBS
- Hawrelak and Myers (2010), open-label uncontrolled pilot of multi-ingredient formulas, 31 patients: Further research is warranted on C-IBS, as a potentially useful therapeutic formula. (Source 3)
- Drugs.com professional monograph (updated Aug 2026), literature summary: no large clinical studies exist, and data are lacking to support use of slippery elm for any indication. (Source 2)
How much
- Reference intake: There is no RDA or AI: slippery elm is an herbal product, not a nutrient. No reference intake was found. (Source 2)
- Upper limit: No upper limit has been set. The reference monograph says contraindications have not been identified but advises avoiding it in pregnancy. (Source 2)
- Studied: Dried powdered slippery elm bark was given as part of two multi-ingredient IBS formulas (with bilberry, agrimony and cinnamon, or with lactulose, oat bran and licorice). The dose is not given in the abstract. (Source 3)
A common belief, and what the research shows
The belief: Slippery elm is proven to soothe the throat and heal the gut.
What the research shows: Controlled evidence is missing. A review of its use for throat inflammation states "no scientific evidence is available to support the validity of slippery elm's use in treating upper airway inflammatory conditions", and its own pilot found "the difference did not reach the level of statistical significance".
Questions and answers
What is it?
Slippery elm is the inner bark of a North American elm tree, dried and powdered. It contains mucilage, which turns into a slippery gel in water. (Source 1)
What does it do in the body?
It is said to coat and soothe the throat and gut. No controlled study has shown that slippery elm alone does this in people. (Source 1)
Is it good or bad for you?
The benefit is unproven, and no side-effect rates are published. It is advised against in pregnancy because of reported abortive effects. Elm oleoresins and pollen can cause allergy. (Source 2)
How do you get more of it?
It is sold as powdered bark, lozenges and capsules. The one IBS study gave dried powdered bark mixed with other ingredients. This describes what was studied, not a suggestion. (Source 3)
If it is harmful, what reduces it?
Does not apply. It is not a body compound, and nothing builds up that needs removing. (Source 2)
Why might someone be low in it or missing it?
Does not apply. Slippery elm is a plant remedy, not a nutrient, so nobody is deficient in it. (Source 1)
Which whole foods contain it or feed it?
No ordinary food contains it. Only the inner bark of the tree is used. (Source 1)
What happens if you do not have it?
Nothing is known to happen. It is not an essential substance. (Source 2)
How can you test for it?
No test for slippery elm intake or levels exists in the literature we searched. (Source 2)
We searched: WebSearch for slippery elm systematic reviews, trials, adverse events and case reports; the Drugs.com professional monograph; the Watts and Rousseau review
References
- Journal of Investigational Biochemistry 1(1):17-23. Slippery elm, its biochemistry, and use as a complementary and alternative treatment for laryngeal irritation. 2012. Read the source
- Drugs.com (Wolters Kluwer). Slippery Elm (professional natural product monograph). 2026. Read the source
- Journal of Alternative and Complementary Medicine 16(10):1065-1071. Effects of two natural medicine formulations on irritable bowel syndrome symptoms: a pilot study. 2010. PMID 20954962, DOI 10.1089/acm.2009.0090. Read the source