Common name: Slippery elm
Other names: Rod elm, Indian elm, red elm
Latin name: Ulmus rubra
Affinities: Digestive system, respiratory system
Actions: Antitussive, demulcent, emollient, nutritive, expectorant
Specific indication: Hot inflamed gut, indigestion with pain, urinary tract inflammation, diarrhea, dry cough
Diseases: Colitis(3), IBS(3), leaky gut syndrome(3), gastric ulcers(3), gastritis(3), acid reflux(3), Crohn’s disease(3), IBD(3)
Parts used: Inner bark
Energetics: Cooling, moistening
Characteristics: Slippery elm is a deciduous tree native to eastern and central U.S.A. and eastern Canada (Kuhn and Winston, 2000). The trunk is reddish-brown with gray-white bark and often grows between 50 and 60 foot tall. Its name arises from the viscous and slimy liquid formed when the inner bark is chewed (Watts et al., 2012).
History: The 1st century Greek physician, Dioscorides, recommended slipper elm bathing to speed the healing of bones (Castleman, 2001). This indication endured some 1,500 years or more. In the 17th century English herbalist Nicholas Culpeper recommended it for healing broken bones when bathing and mentioned the leaves could be applied topically for wound healing. The native Americans used American slippery elm bark as food and medicine for wounds, sore throats, coughs, and other health problems. Later, in the 19th century Thomsonian herbalists used slippery elm tea as a laxative gentle enough for children. In the time of the American Civil War, slippery elm was used to treat gonorrhoea, syphilis, and haemorrhoids. The Eclectic physicians recommended a tablespoon of the powder boiled in milk for a nourishing diet for infants newly weaned to prevent bowel complaints they are subject to.
Current applications: David Hoffman in Holistic Herbal mentions that slippery elm bark is a soothing nutritive demulcent which is well suited for sensitive or inflamed mucous membrane linings in the digestive system (Hoffman, 1988). He says it combines well with marshmallow for digestive problems. Thomas Bartram mentions that its blanketing action protects the gastric mucosa from… too much acid. He recommends it for acid reflux, digestive inflammation, indigestion, and gastric or duodenal ulcers. Maria groves has similar recommendations, but also includes dry cough and urinary tract inflammation in her indications (Groves, 2016).
Science: The abundant medically relevant components of slippery elm are called the mucilage and tannins (Watts et al., 2012). The mucilage forms the majority of chemical compounds in slippery elm and is comprised of carbohydrates which in water, swell to form a viscuous and sticky substance. This substance coats mucosal membranes and helps calm adverse sensations and involuntary reflexes (coughs, throat clearing). The tannins are phytochemicals that possess astringent properties, tannins have been used in the treatment of inflamed superficial skin diseases, shingles, and eczema. They also have antibacterial properties which may be why slippery elm was used for wound healing. Slippery elm has anti-oxidant activities ex vivo (Langmead et al., 2002). There are no scientific studies of human disease to date.
Safety: High. However, slippery elm may interfere with the absorption of pharmaceutical drugs taken at the same time. WebMD recommends taking it at least one hour before or after taking other medication.
Dosage: Can be used in capsules or powdered in drinks. David Hoffman recommends, use 1 part powdered bark to 8 parts water, mix powder together initially in a little water before adding the rest (Hoffman, 1988). Bring to the boil and simmer gently for 10-15 minutes, then drink half a cup three times a day. Up to 12 400mg capsules may be taken per day, however a tea is preferable.
Research on models
Anti-oxidant activity: One study found that slippery elm extract in vitro has anti-oxidant abilities and scavenged free radicals (Langmead et al., 2002).
Bartram, Thomas. Bartram’s encyclopedia of herbal medicine. Hachette UK, 2013.
Castleman, Michael. “The new healing herbs.” Bantam Book, New York (2001): 465-471.
Groves, Maria. Body into Balance. Storey Publishing, 2016.
Hoffman, David. Holistic herbal. Element Books, 1988.
Kuhn, Merrily A., and David Winston. Herbal therapy and supplements: a scientific and traditional approach. Lippincott Williams & Wilkins, 2000.
Langmead, L., et al. “Antioxidant effects of herbal therapies used by patients with inflammatory bowel disease: an in vitro study.” Alimentary pharmacology & therapeutics 16.2 (2002): 197-205.
Watts, Christopher R. “Slippery elm, its biochemistry, and use as a complementary and alternative treatment for laryngeal irritation.” Journal of Investigational Biochemistry 1.1 (2012): 17-23.