YahGarden

Herb library · Herb · Ulmus rubra (U. fulva)

Slippery elm

The inner bark of a North American elm, which turns slippery and gel-like in water. It is sold in lozenges for sore throats and as a powder for an upset stomach; it is considered safe, but it has not been tested on its own in people.

Traditional use

Native to the eastern and central United States and Canada. Native Americans used the inner bark for digestive and urinary complaints and on the skin. In 19th-century American medicine it was a soothing drink for coughs, sore throat and bowel complaints, a food for weaned infants, and a poultice. Today it is sold in lozenges for sore throat and as a powder or capsule for digestive upset, and it is designated generally recognized as safe (GRAS). Melvin Gilmore recorded (1919) that the Omaha drank a decoction of the fresh inner bark as a laxative and cooked the bark with buffalo fat to flavor the tallow and keep it from going rancid.

What studies show

No studies in people of this herb on its own yet. What is known of it comes from the traditions that use it.

  • Insufficient

    Sore throat, heartburn and digestive upset: no clinical trial of slippery elm on its own was found. A small uncontrolled 2010 pilot in irritable bowel syndrome used mixtures that contained it along with other ingredients, and a 2019 review of reflux remedies found a wide gap between anecdote and evidence.

Be careful of

Cautions

  • NoteIt is generally recognized as safe, and there are no reports of liver injury. Rare allergic skin reactions have been linked to it.
  • Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.

From the old books

What herbals and dispensaries of the past printed. History, in their words.

“The fresh inner bark was boiled and the resulting decoction was drunk as a laxative. The Omaha used to cook the inner bark with buffalo fat in rendering out the tallow. They considered that the bark gave a desirable flavor to the fat and added a preservative quality, preventing it from becoming rancid.”
Melvin Randolph Gilmore, Uses of Plants by the Indians of the Missouri River Region (1919), p. 76. See the page of Uses of Plants by the Indians of the Missouri River Region, p. 76 (opens in a new tab) · Read the full passage from Uses of Plants by the Indians of the Missouri River Region, p. 76
“Notwithstanding its general value as an application to ulcers, it will often be found injurious, especially when used as a cataplasm to ulcers of the limbs, rendering the ulcer more irritable and difficult to heal”
Harvey Wickes Felter and John Uri Lloyd, King's American Dispensatory (1905), vol. 2, p. 2013. See the page of King's American Dispensatory, vol. 2, p. 2013 (opens in a new tab) · Read the full passage from King's American Dispensatory, vol. 2, p. 2013

Sources

  1. Slippery Elm - LiverTox: Clinical and Research Information on Drug-Induced Liver Injury (opens in a new tab) · NIH · read September 25, 2026
  2. Effects of two natural medicine formulations on irritable bowel syndrome symptoms: a pilot study (J Altern Complement Med, 2010) (opens in a new tab) · NIH · read September 25, 2026
  3. Popular Remedies for Esophageal Symptoms: a Critical Appraisal (Curr Gastroenterol Rep, 2019) (opens in a new tab) · NIH · read September 25, 2026

Reviewed September 25, 2026.