What Is Slippery Elm?

An Herbal Treatment Believed to Treat Sore Throat and IBS

Slippery elm powder, tea bags, and tincture

Verywell / Anastasia Tretiak

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Slippery elm (Ulmus rubra) is a type of elm tree. It is found in eastern North America from southern Quebec to northern Florida and eastern Texas.

In traditional Native American medicine, the inner bark of slippery elm is used to treat wounds and gastrointestinal ailments. Slippery elm is also a main ingredient in essiac tea, an herbal tea said to support the immune system.

Slippery elm contains soluble fiber, which is a fiber that dissolves in liquid. The soluble fiber found in slippery elm is called mucilage.

Mucilage traps and absorbs water, forming a gel-like substance. This substance is a demulcent, which means it forms a coating over mucous membranes. The coating may provide short-term relief of pain and inflammation.

Slippery elm also contains calcium. The calcium may act as a mild antacid.

Unfortunately, research on the effects of slippery elm is limited. Many of the existing studies are small and dated.

Slippery elm has many names, including:

  • Red elm
  • Gray elm
  • Soft elm
  • Moose elm
  • Indian elm

Slippery elm should not be confused with American elm (U. americana). American elm looks similar but has no medicinal uses.

What Is Slippery Elm Used For?

Slippery elm has a long history of use in herbal medicine. It is either taken by mouth or applied topically to the skin. Some of the conditions slippery elm is believed to treat include:

It is also applied topically to the skin to help cuts and burns heal.

Some proponents say slippery elm can treat other more serious illnesses, like:

To date, there is no clinical evidence to support these claims. Here's what is known about a few specific uses.

Sore Throat

Slippery elm started appearing in commercial medicines in the 1840s when a physician named Henry Thayer used it to make an elixir. Thayer's formula was first sold as an oral suspension, and later as lozenges.

As a natural demulcent, slippery elm can soothe a sore throat. It does this by coating the lining of the throat and esophagus.

Thayer's Slippery Elm Lozenges are still being sold today. The company also makes a slippery elm lip balm. Other manufacturers produce slippery elm extracts, tinctures, lotions, and herbal teas.

In the 1960s, the Food and Drug Administration classified slippery elm as a botanical drug. It is believed safe for the treatment of minor sore throat pain.

The agency did not say whether it was effective, though. Instead, they called it "a demulcent with limited clinical effects."

Digestive Disorders

Slippery elm is believed by some to relieve the symptoms of acid reflux. Unfortunately its action lasts only around 30 minutes. It also does not treat the underlying causes of reflux.

Advocates of slippery elm also claim it can ease many of the symptoms of inflammatory bowel disease (IBD). IBD includes ulcerative colitis and Crohn's disease.

Proponents believe slippery elm forms a temporary protective barrier in the intestines. To date, the evidence of this is mixed.

A 2002 study found that slippery elm has antioxidant effects on colon tissue samples from people with ulcerative colitis. The study did not show whether the same effect would occur if slippery elm was taken by mouth.

Other scientists have looked into whether slippery elm can control the symptoms of irritable bowel syndrome (IBS). IBS can be either constipation-predominant (IBS-C) or diarrhea-predominant (IBS-D).

A study published in 2010 looked at two different formulations containing slippery elm. The study found that all of the IBS-C subjects who took the supplements reported improvement in their symptoms. Around 75% of those with IBS-D reported similar improvements.

The results of this small study are promising, but more research is needed.

Recap

There is some evidence that slippery elm may help certain digestive conditions, but the research is mixed. Many of the studies are small and dated. More research is needed.

Possible Side Effects of Slippery Elm

Because there isn't much research, the safety of slippery elm hasn't been established. Common side effects include:

Slippery elm may coat the digestive tract. Because of this, it may interfere with the absorption of certain drugs.

If you are taking other medications, take slippery elm at least two hours before or after your other drugs. When you take your regular medications, drink plenty of water unless otherwise indicated.

In folk medicine, the outer bark of the slippery elm tree is sometimes used to induce abortion. There is little evidence that this works. Still, people who are pregnant or intend to become pregnant should avoid slippery elm.

Recap

Slippery elm may cause side effects, and some people may be allergic to it. It may also interfere with absorption of other drugs. Take slippery elm at least two hours before or after your other medications. If you are or trying to become pregnant, avoid taking slippery elm.

Slippery elm powder
Verywell / Anastasia Tretiak

Dosage and Preparation

There are no guidelines for the use of slippery elm. Slippery elm is considered safe as a short-term treatment of sore throat. This does not necessarily mean it is safe for other uses. As a general rule, don't take more than the recommended dosage on the product label.

Slippery elm remedies are typically made from the powdered inner bark of the tree. Slippery elm can be purchased in many different forms, including:

  • Tinctures
  • Lozenges
  • Salves
  • Lip balms
  • Bulk powder
  • Tea bags

What to Look For

Dietary supplements are not closely regulated in the United States. They do not need to undergo rigorous testing or research. Because of this, quality can vary between brands.

Always purchase supplements from well-known brands. Look for products that have been quality tested by a third party. U.S. Pharmacopeia or ConsumerLab are examples of organizations that do this kind of testing.

Unfortunately, manufacturers of herbal supplements rarely submit products for third-party testing. This means you may have to use your best judgement. Try not to be swayed by health claims that may or may not be true.

Recap

Always look for supplements made by well-known brands. Don't take more than the dose recommended on the label.

Other Concerns

Slippery elm is not yet an endangered species. Still, there are grave fears about its sustainability.

Slippery elm prefers floodplain habitats. Many of these habitats have been developed for human uses. Slippery elm timber has limited commercial value, so there hasn't been much effort to replant these trees.

Because slippery elm is also vulnerable to Dutch Elm Disease, there are very few mature slippery elm trees left in nature. 

Slippery elm is currently on the "special concern" list in Rhode Island. It is believed to have been eradicated from Maine.

Wild-harvested slippery elm bark threatens the species' survival. You can help protect the species by avoiding slippery elm bark harvested from wild trees.

Summary

The inner bark of the slippery elm tree is used for a number of health problems, including sore throat and certain digestive disorders. Research on the effectiveness of slippery elm is limited.

Slippery elm may have side effects, including nausea and skin irritation. Some people may be allergic to slippery elm.

There are no guidelines for the use of slippery elm. It is considered safe for short-term treatment of sore throat. When taking it for other conditions, always use the recommended dosage. Look for products made by well-known brands.

Slippery elm is a vulnerable species. You can help protect this tree by avoiding wild-harvested bark.

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3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. MedlinePlus. Slippery elm. Updated November 5, 2017.

  2. Langmead L, Dawson C, Hawkins C, Banna N, Loo S, Rampton DS. Antioxidant effects of herbal therapies used by patients with inflammatory bowel disease: an in vitro study. Aliment Pharmacol Ther. 2002;16(2):197-205.

  3. Hawrelak JA, Myers SP. Effects of two natural medicine formulations on irritable bowel syndrome symptoms: a pilot study. J Altern Complementary Med. 2010;16(10):1065-1071. doi:10.1089/acm.2009.0090

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