Slippery Elm Bark in Essiac Tea: Uses, History & Research
Slippery elm bark is one of the eight ingredients in the Genuine Essiac™ formula. It comes from Ulmus rubra, a deciduous tree native to eastern and central North America. Unlike the roots, leaves, and seaweed used elsewhere in the blend, this ingredient comes from the tree’s inner bark. 1
Slippery elm has a long history in North American botanical traditions. Its best-known feature is its mucilage: naturally occurring plant polysaccharides that develop a characteristic slippery texture when mixed with water. 3
In Genuine Essiac™, slippery elm bark is included in a specific proportion as one component of the complete eight-herb formula.
What Is Slippery Elm Bark?
Slippery elm (Ulmus rubra), also historically called Ulmus fulva, belongs to the elm family, Ulmaceae. Other common names include red elm and moose elm. It is native to broad areas of the eastern and central United States and parts of eastern Canada. 1 2
The ingredient used in traditional herbal preparations is the inner bark, not the rough outer bark, leaves, or wood. When the inner bark is moistened, its mucilage creates the texture that gives the tree its common name. 3
A North American Tree With a Long History
The USDA documents historical uses of slippery elm by several Indigenous North American peoples, including use of inner-bark fibers for ropes, baskets, bags, and other practical purposes. Ethnobotanical records also describe traditional preparations made from the bark. 1
Early European settlers subsequently adopted some traditional uses of slippery elm. Dried inner bark became a familiar ingredient in powdered preparations, beverages, and lozenges. These accounts describe historical practices; they do not establish that a modern slippery elm preparation treats any medical condition. 3 5
Slippery Elm Bark and the Eight-Herb Essiac Formula
The Essiac name is associated with different formulations. Some contain four herbs, while Genuine Essiac uses an expanded eight-ingredient formula.
The complete Genuine Essiac™ formula contains:
- Burdock root
- Sheep sorrel, including the root
- Slippery elm bark
- Turkish rhubarb root
- Red clover
- Watercress
- Blessed thistle
- Kelp (Ascophyllum nodosum)
Each ingredient is included in a specific proportion as part of the complete blend. Research about slippery elm bark alone should not be assumed to describe the effects of Genuine Essiac tea.
What Is Naturally Found in Slippery Elm Bark?
The inner bark contains several classes of naturally occurring compounds. Its most distinctive characteristic is its water-interacting mucilage. 3 5
Mucilage
Mucilage is a mixture of complex polysaccharides. When exposed to water, these substances hydrate and create a thick, slippery consistency. Researchers describe slippery elm mucilage as containing various sugar units, including pentoses, hexoses, and uronic-acid components. 5
The texture of mucilage helps explain why slippery elm has been used in traditional water-based preparations. The presence of mucilage does not, by itself, demonstrate a clinical benefit from consuming the ingredient in a multi-herb tea.
Tannins and Other Plant Compounds
Slippery elm bark also contains tannins, starches, and other naturally occurring plant constituents. The relative amounts can vary with the botanical material and how it is processed. 3
Minerals and Other Constituents
Published botanical discussions describe naturally occurring minerals and additional constituents in slippery elm bark. However, the presence of a nutrient in raw bark does not establish the amount delivered by a brewed serving of Genuine Essiac. For product-specific nutritional information, consult our Nutrition Facts and available analysis.
Traditional Uses of Slippery Elm Bark
Water-Based Herbal Preparations
Historically, powdered slippery elm inner bark was mixed with water to produce a thick preparation. Its distinctive consistency led to its use in traditional drinks and other preparations. 3
Lozenges and Botanical Products
Slippery elm has also been used in throat lozenges and other botanical products. This is a description of historical and commercial uses, not a claim that Genuine Essiac treats sore throats or other conditions. 4
Traditional External Applications
Historical accounts describe moistened slippery elm bark in poultices and other external preparations. Those uses differ from drinking a brewed herbal tea, and evidence for one preparation cannot be automatically transferred to another. 1
What Does Modern Research Tell Us?
Much of the literature on slippery elm concerns its chemistry, traditional use, or inclusion in multi-ingredient products. High-quality human research on slippery elm alone remains limited. 4 7
Some small clinical studies have evaluated formulas containing slippery elm alongside other ingredients. Because multiple ingredients were used, such studies cannot isolate slippery elm’s contribution, and they do not establish the effects of Genuine Essiac.
Laboratory observations about isolated polysaccharides or other constituents also should not be interpreted as proof of health outcomes in people drinking a finished herbal tea. There is insufficient clinical evidence to claim that slippery elm or Essiac prevents, treats, or cures cancer or other diseases. 4
Why Slippery Elm Sourcing Matters
Slippery elm deserves particular attention because harvesting inner bark can harm or kill trees when done improperly. United Plant Savers includes the species on its at-risk list, citing commercial harvest pressure, disease, and concerns about wild populations. 5 6
Important sourcing considerations include:
- Correct identification as Ulmus rubra
- Confirmation that the material is inner bark
- Responsible harvesting and traceable supply chains
- Appropriate drying and storage
- Botanical identity and consistency
- Microbial quality and contaminant controls
- Supplier documentation and finished-product testing
How We Source Our Slippery Elm Bark
Genuine Essiac obtains botanical ingredients through established suppliers and incorporates quality-control procedures for the finished eight-herb formula. Learn more about our herb sourcing and testing.
Because responsible sourcing is especially important for slippery elm, species identity, plant part, supplier documentation, and harvesting practices are relevant questions. Specific sustainability certifications or harvesting methods should only be claimed when verified by supplier records.
Slippery Elm Bark in the Genuine Essiac Formula
Slippery elm is the bark ingredient in the Genuine Essiac eight-herb blend. It contributes a different botanical origin and chemical profile from the formula’s roots, flowering plants, leafy herbs, and marine seaweed.
Understanding slippery elm individually provides useful context, but findings about the bark or its isolated constituents cannot automatically be attributed to the complete tea formula.
Slippery elm bark responds in different ways with variations in growing seasons. You can learn more about the texture of slippery elm bark in general as well as expected variations of the consistency.
Frequently Asked Questions About Slippery Elm Bark and Essiac
Genuine Essiac contains slippery elm bark from Ulmus rubra, a tree native to North America.
The inner bark is the part traditionally used in herbal preparations.
Its naturally occurring mucilage hydrates when exposed to water, creating a characteristic slippery consistency.
No. Slippery elm is Ulmus rubra, while American elm is Ulmus americana. They are different species.
Yes. Mucilage is one of its best-known natural constituents.
Slippery elm bark appears in both traditional four-herb and expanded eight-herb Essiac formulations, although formulations and ingredient proportions can differ.
Not necessarily. Individual sensitivities, pregnancy, medication use, and other circumstances may affect suitability. Its mucilage may interfere with the absorption of some oral medications when taken together. Consult a qualified healthcare professional if you have questions about using herbal products.
Because slippery elm contains mucilage, taking it alongside oral medications may affect absorption. Ask a pharmacist or healthcare professional about appropriate separation.
No. Research on an individual herb or isolated compound does not establish the effects of the complete eight-herb formula.
Removing inner bark can damage or kill a tree. Responsible sourcing is important because of harvesting pressure and tree diseases.
Understanding Slippery Elm’s Place in Essiac
Slippery elm bark is distinctive among the eight Genuine Essiac ingredients because it comes from the inner bark of a North American tree and naturally contains mucilage. Its botanical identity, traditional history, and sourcing considerations are important parts of understanding the ingredient.
Its role is best understood within the complete eight-herb formula, not as a standalone substitute or as proof of any particular medical effect.
Explore all eight Essiac ingredients to learn more about their origins and characteristics.
Last Updated: 10/08/2026
1 USDA NRCS, Slippery Elm Plant Guide.
2 US Forest Service, Ulmus rubra species review.
3 NIH LiverTox, Slippery Elm.
4 Memorial Sloan Kettering, Slippery Elm.
5 Burkhart EP, Slippery Elm in the Herbal Marketplace, United Plant Savers.
6 United Plant Savers, Slippery Elm Species Profile.
7 Drugs.com Natural Products, Slippery Elm.
8 Natural Products in the Management of Gastroesophageal Reflux Disease, 2025.
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About the Author
Bryan Paulhus
Founder & CEO, Genuine Essiac
Bryan Paulhus is the Founder & CEO of Genuine Essiac. For more than 40 years, he has researched the authentic 8-herb Essiac formula and writes to help readers better understand its history, preparation, and quality standards.
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