Slippery Elm
Ulmus rubra
红榆树皮
Pinyin: Hóng Yú Shù Pí
Plant Family
Ulmaceae
Part Used
Inner bark
Origin
Eastern North America (United States, Canada)
Safety Level
Safe
Overview
Slippery elm is a tree native to eastern North America whose inner bark has been used as medicine and food by Native Americans for centuries. The bark becomes very slippery and mucilaginous when mixed with water, which gives it its soothing and protective properties. Slippery elm is valued for its ability to soothe irritated mucous membranes throughout the digestive, respiratory, and urinary systems.
Traditional Chinese Medicine Properties
Nature (四气)
neutral / slightly cool
Flavors (五味)
sweet, bland, slippery
Meridians (归经)
stomach, large intestine, lung, bladder
Health Benefits
Traditional Uses
- Soothes digestive tract: ulcers, gastritis, colitis, diarrhea
- Coughs and sore throats (demulcent)
- Urinary tract irritation and cystitis
- Wound healing and skin conditions (topical poultice)
- Nutritive tonic for convalescence
- Heartburn and GERD
- Bowel regularity (bulking and soothing effect)
- Hemorrhoids (topical)
Active Constituents
The key compounds responsible for this herb's therapeutic effects:
Usage & Dosage
How to Use
Powder mixed with water (slippery elm gruel), tea, capsule, tablet, lozenge, syrup, poultice (topical), suppository (for hemorrhoids). Best taken between meals, not with medications (may reduce absorption).
Suggested Dosage
Powder: 1–3 tsp (3–9 g) mixed with warm water, 2–3x/day; capsules: 300–500 mg 2–3x/day; lozenges: as needed for cough/sore throat. Mix powder with cold water first, then add warm water to prevent clumping. For digestive issues: take 30–60 minutes before meals or on empty stomach.
Quality & Storage
Harvest Season
Inner bark is harvested in spring (April–May) when sap is rising and bark is most easily peeled. Only the inner bark (phloem) is used; the outer cork bark is discarded. Sustainable harvesting is important since removing too much bark can kill the tree. Look for sustainably wild-harvested or cultivated slippery elm.
Quality Indicators
High-quality slippery elm: fine, light brown to reddish-brown powder, very slippery/mucilaginous when mixed with water, mild slightly sweet odor. When mixed with water, it should form a thick, slippery gel. Coarse or gritty powder is lower quality. Look for sustainably harvested products (the tree has been overharvested in some areas). Inner bark only (not outer bark).
Storage
Powder: airtight container in cool dry place, 1–2 years. Protect from moisture (it absorbs water easily). Keep tightly sealed. Slippery elm can go rancid if stored improperly.
Safety Information
Contraindications
Pregnancy and breastfeeding (generally considered safe, but insufficient data - consult practitioner)Children (generally safe - start with small amounts)Bowel obstruction (bulking effect may worsen)Those with difficulty swallowing (thick mixture may be hard to swallow - mix with plenty of water)Take medications at least 2 hours before or after slippery elm (may reduce absorption)Rare allergy to elm treesGenerally very safe for most people
Possible Side Effects
- Extremely safe and well-tolerated for most people
- Mild allergic reaction (very rare)
- Bloating or gas (if taken in too large a quantity)
- May affect nutrient absorption if taken in very large amounts long-term
- Rare: constipation or diarrhea (individual variation)
- Very low side effect profile overall
Drug Interactions
- Oral medications of any kind - may reduce absorption due to mucilage coating (take 2 hours apart)
- Blood thinners (mild effect from vitamin K - minimal at normal doses)
- Insulin and diabetes medications (may slightly lower blood sugar - monitor)
- Generally very low interaction potential if taken 2 hours apart from medications
- Interactions are primarily due to physical coating effect, not biochemical
Note: Always consult with a qualified healthcare practitioner before starting any herbal supplement, especially if you are pregnant, nursing, have medical conditions, or take medications.
References & Research
Information on this page is based on traditional herbal knowledge and modern scientific research. For a comprehensive list of references, please refer to our full citations page.
ℹ️ Disclaimer
This information is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. The FDA has not evaluated these statements. Always consult a qualified healthcare provider before using herbal supplements.
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