Slippery elm: what it may help, the evidence, and how to take it
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- Slippery elm inner bark capsules. Best for: Adults who want a simple single-herb capsule. See options on Amazon
- Slippery elm bark powder. Best for: People who prefer to mix a drink or adjust the amount. See options on Amazon
- Slippery elm lozenges. Best for: A scratchy throat or minor cough. See options on Amazon
What slippery elm is
Slippery elm is a tree native to North America. Memorial Sloan Kettering Cancer Center (MSK) says its bark is used for digestive disorders, sore throat, cough and skin ulcers. Supplements use the inner bark; NOW Foods lists Ulmus rubra inner bark on its label.
The key ingredient is mucilage. MSK explains that its insoluble polysaccharides form a thick, slippery material when mixed with water. That is why slippery elm is called a demulcent, a substance that coats and soothes irritated tissue. MSK adds that its fiber is thought to act as a bulk-forming laxative.
What the research shows
| Use | What MSK reports |
|---|---|
| Minor cough, sore throat | May help; human data lacking |
| Constipation-type IBS | One small study of a formula containing slippery elm improved symptoms |
| Diarrhea | Evidence lacking |
| Skin sores (topical) | Thought to soothe; human data lacking |
| Cancer, infections | No evidence |
Sore throat and cough. The mucilage is thought to coat and calm an irritated throat, which is why slippery elm appears in lozenges and teas. MSK notes human data are lacking.
Digestion. In a small pilot study, a formula that included slippery elm improved bowel habits and symptoms in people with constipation-predominant irritable bowel syndrome. Because it was a combination formula, the effect of slippery elm alone is unknown.
Lab studies. Slippery elm showed antioxidant activity in lab tests, including in bowel tissue samples from people with active ulcerative colitis. Lab results do not show it treats colitis.
Essiac. Slippery elm is one ingredient in Essiac, an herbal formula promoted as an alternative cancer treatment. MSK says evidence is lacking for slippery elm as a cancer treatment.
Medicine timing and safety
- Separate from medicines. Nature's Way says slippery elm should not be taken together with any medication because it may interfere with absorption. Ask your pharmacist how far apart to take them.
- Pregnancy and nursing. NOW Foods says pregnant or nursing women should not use it unless recommended by a physician.
- Medical conditions. Both labels advise consulting a professional if you take medication or have a medical condition.
- Adults. NOW Foods labels its product for adults only.
- Limits. MSK says there is no evidence it can treat infections, cancer or other serious conditions.
Capsules, powder, lozenges or drops?
- Capsules. NOW Foods gives 800 mg of inner bark per 2 capsules, taken 1 to 3 times daily. Nature's Way gives 1.6 g of bark per 4 capsules, taken twice daily with warm water between meals.
- Bark powder. Mixing powder with water shows the mucilage at work and lets you adjust the amount. Follow the package directions.
- Lozenges. Sold for scratchy throats; check sugar content.
- Liquid drops. Often blended with marshmallow root or DGL licorice. Check every ingredient.
- Gut blends. Many gut formulas add glutamine, aloe or other herbs, which makes it hard to know what is working and adds cautions. See our DGL licorice guide for that ingredient.
How to choose slippery elm
- Inner bark of Ulmus rubra. Look for this on the label.
- Single herb for a fair trial. Choose slippery elm alone if you want to see how you respond to it.
- Plan your medicine schedule. Pick a time of day well apart from your other medicines.
- Drink enough water. Labels such as Nature's Way direct taking it with water.
- Third-party testing. Prefer brands that state quality testing.
When to see a doctor
A sore throat or cough that lasts, gets worse, or comes with high fever or trouble breathing needs medical care. So do ongoing changes in bowel habits, blood in the stool or unplanned weight loss. Slippery elm is not a substitute for diagnosis or treatment.
What to look for when you buy
Slippery elm inner bark capsules
Best for: Adults who want a simple single-herb capsule
NOW Foods lists 800 mg of Ulmus rubra inner bark per 2 capsules, taken 1 to 3 times daily.
Watch out: Take apart from medicines. Not for pregnancy or nursing unless your doctor recommends it.
See options on AmazonSlippery elm bark powder
Best for: People who prefer to mix a drink or adjust the amount
Powder mixed with water forms the soothing mucilage gel and lets you control the serving.
Watch out: Follow package directions and keep it apart from medicines.
See options on AmazonSlippery elm lozenges
Best for: A scratchy throat or minor cough
Lozenges are made for minor throat irritation, where MSK says slippery elm may help.
Watch out: Check sugar content. See a doctor for a sore throat that lasts or comes with fever.
See options on AmazonQuestions people ask
- What is slippery elm good for?
- It may help a minor cough or sore throat, and one small study of a formula containing it helped constipation-type IBS. It has not been shown to treat infections or serious conditions.
- How do you take slippery elm?
- Follow the label. NOW Foods directs 2 capsules 1 to 3 times daily; Nature's Way directs 4 capsules twice daily with warm water between meals.
- Can I take slippery elm with my medicine?
- Take it separately. Nature's Way says it may interfere with medicine absorption. Ask your pharmacist about timing.
- What is slippery elm mucilage?
- A fiber that forms a thick, slippery gel with water and is thought to soothe irritated tissue.
- Is slippery elm safe during pregnancy?
- NOW Foods says not to use it during pregnancy or nursing unless your physician recommends it.
Sources
- Slippery Elm: About Herbs (mskcc.org), Memorial Sloan Kettering Cancer Center
- Slippery Elm 400 mg Veg Capsules (www.nowfoods.com/products/supplements/slippery-elm-400-mg-veg-capsules), NOW Foods
- Slippery Elm Bark (naturesway.com), Nature's Way