Slippery elm

Slippery elm is a valuable herbal medicine that has a long history of use for conditions of the digestive system and skin. However, due to threat of over-harvesting in the wild, we advise that this plant is not for home use unless it can be confidently procured from a sustainable (non-wild harvested) source. Marshmallow root powder is the perfect substitute for this plant as it bestows much the same properties. See ‘sustainability’ for more information.

Slippery elm is a soothing, nutritive, demulcent that targets sensitive or inflamed mucous membranes throughout the body, but with a specific action on the skin and digestion. 

It is also an astringent and has the dual action of soothing and astringing inflamed linings. Slippery elm produces mucilage that will coat inflamed linings, allowing any damaged tissue under the surface to regenerate and repair effectively. 

The mucilage produced by the plant also acts as an excellent bulk laxative in cases of chronic and acute constipation but also as a wound packer that will draw out heat and infection from inflamed minor wounds. 

The powdered bark may be added to a little hot water or vegetable glycerin to create a ‘drawing agent’. This can be applied like a poultice over a wound, a thorn in the skin, abscesses or whitlow to draw out the toxins and bring to head. The combined action of mucilage and astringency acts to create a suction over the surface area on which it is applied. This can also be used to help draw out splinters or any remanence from an insect bite or sting. Marshmallow root powder is equally as effective for this application.

Mucilage is the primary medicinal component of the plant and has a similar chemical composition to the mucilage present in linseed.

Slippery elm bark is classed as a demulcent with anti-inflammatory activity that is focused within the digestive tract and on the skin. 

Energetically slippery elm is best for dry, atrophic or inflamed conditions. The cooling and moistening demulcent properties are largely due to the high levels of mucilage found in the bark.

This quality makes slippery elm a fantastic anti-inflammatory and vulnerary with an affinity for the digestive, respiratory and integumentary system. It is long used as a medicine for convalescence, because as a deeply nutritive and fiber-rich bulk, it can nourish the body and restore tissue integrity in the gastrointestinal tract.

This mucilaginous quality also helps to absorb and draw out excess heat, infection or debris from minor wounds or inflamed mucous membranes encouraging effective wound repair mechanisms. It is indicated in any generalised inflammation of the digestive tract including gastritis, duodenal ulcers, haemorrhoids, constipation, diarrhoea, dysentery and enteritis.

This drawing action is also understood to act upon the mucosal linings inside the visceral organs to allow for improved cellular detoxification (3).

The bark was traditionally used as an external treatment for burns, ruptures, skin complaints and wounds and is considered to be naturally incredibly soothing and nourishing for the whole body.

Slippery elm was considered to be one of the best demulcent and internal and external uses. It was used as a lubricant to sooth alimentary mucosa, relieving intestinal irritation. It was also said to quieten the nervous system (4).

The elm leaves and bark are classed as demulcents with anti-inflammatory activity that is focused within the digestive tract but also on the skin.

Digestive system

Slippery elm has a wide range of applications for gastrointestinal health. It may be applied to treat gastric or duodenal acidity or ulcerations. Conditions such as heartburn and reflux or chronic constipation may also be improved through the internal use of this medicine. However it is important to note that other causative factors should always be identified for such ongoing conditions (2).

The other indications for slippery elm are for any such conditions with general inflammation of the digestive tract. These may include gastritis, haemorrhoids, constipation, diarrhoea, dysentery and enteritis. There are more serious conditions that herbs like slippery elm may be used such as for inflammatory bowel disease, Crohns disease and diverticulosis/itis (2). These more chronic diseases are treated by a medical herbalist as part of a holistic approach alongside other specific herbs and interventions.

Slippery elm can be a valuable medicine in these conditions as it is also considered to be incredibly soothing and nourishing for the whole body taken internally as a nutritive food.

Respiratory system

Slippery elm may be indicated for dry, unproductive type coughs. As a soothing demulcent the potential of this plant to reduce inflammation in the mucosa of the respiratory tract may see it being used for a number of conditions such as pharyngitis, pneumonia and pleurisy (2).

Skin

The bark is traditionally used as an external treatment for burns, infected or inflamed wounds and other ruptures and skin complaints. Additionally, the external application of slippery elm is indicated in other skin inflammations and irritations such as abrasions, minor burns, scalds, boils and abscesses.

Ulcerative colitis

An in vitro study was carried out to investigate the antioxidant effects of herbal therapies used by patients with inflammatory bowel disease. Some of the herbs used were slippery elm, fenugreek, devil’s claw, tormentil and wei tong ning. 

Chemiluminescence was used to identify the effects of the herbs on oxygen radicals under mucosal biopsies taken from patients with active ulcerative colitis. It is unclear whether the herbs were applied in combination or individually for this study. The results showed that oxygen radical release from biopsies was reduced after incubation.

The study concludes that all six herbs have antioxidant effects. Slippery elm, along with the other herbs, was found to elicit a similar response in patients with ulcerative colitis, when compared with 5-aminosalicylic acid. Further investigation is needed to assess the effects of slippery elm as a novel therapy in inflammatory bowel disease (6). 

Irritable bowel syndrome

A pilot study which included 31 patients with irritable bowel syndrome. The patients in the study received either one of two formulas depending on whether they were diarrhoea or alternating bowel habit-predominant (formula 1) or constipation prominent (formula 2). The first consisted of a mixture of dried, powdered bilberry fruit, slippery elm bark, agrimony aerial parts, and cinnamon quills. The second formula consisted of a mixture of dried powdered slippery elm bark, lactulose, oat bran, and liquorice root. 

Patients in either group showed significant increase in bowel movement frequency, and a reduction in abdominal pain, straining, flatulence and global IBS symptoms. The latter formula was associated with the addition of stool consistency improvements. The study concludes that formula 1 was not effective in improving bowel habit in individuals with diarrhoea – predominant or alternating bowel habit although it did significantly improve IBS symptoms generally. Formula 2 significantly improved both bowel habit and IBS symptoms in patients with constipation-predominant IBS (7).

Laryngeal / Pharyngeal irritation

A randomised control single blind design was used to investigate the effects of slippery elm on pharyngeal/ laryngeal sensations. 24 participants were recruited to take either a hot liquid preparation either containing slippery elm powder or placebo. The group who received slippery elm reported a higher rating of soothing sensations than that which was reported by the placebo group (7).

In some traditions, elm was known as ‘chew-bark’ as both animals and humans would self-medicate by chewing the bark of this tree when they had an upset digestion.

Slippery elm can be found in North Dakota to Texas and over to the Atlantic Ocean. It grows in parts of every state except for Alaska, Arizona, California, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming. 

It is also found in the Canadian provinces of New Brunswick, Ontario, and Quebec. Slippery elm trees prefer part to full sun and moist, limestone filled soil. The trees grows best in riparian forests and buffers—areas of forested land along the edges of freshwater or rivers (1).

There are many references to sustainability concerns for this species as it has become ever more popular as an over the counter herb for digestive issues. According to United Plant Savers, a number of threats are faced by this species. 

Both over harvesting in the wild and the increase in Dutch Elm disease mean that there are very few mature slippery elm trees left in the wild. Harvesting healthy trees for lumber or bark is likely to make the tree more vulnerable to disease and reduce its resistance from the gene pool (1). 

Due to the declining wild populations of slippery elm, herbalists often advise not use any wild-harvested bark – unless harvested from naturally felled trees. Marshmallow (Althaea officinalis), mullein (Verbascum spp.) or powdered psyllium husk are equally as effective in the treatment of most conditions for which slippery elm may be applied (1).

Habitat loss and over harvesting from the wild are two of the biggest threats faced by medicinal plant species. There are an increasing number of well-known herbal medicines at risk of extinction. We must therefore ensure that we source our medicines with sustainability in mind. 

The herb supplement industry is growing at a rapid rate and until recent years a vast majority of medicinal plant produce in global trade was of unknown origin. There are some very real and urgent issues surrounding sustainability in the herb industry. These include environmental factors that affect the medicinal viability of herbs, the safety of the habitats that they are taken from, as well as the welfare of workers in the trade.

The botanical supply chain efforts for improved visibility (transparency and traceability) into verifiably sustainable production sites around the world is now certificated through the emergence of credible international voluntary sustainability standards (VSS). Read our article on sustainable sourcing of herbs to learn more about what to look for and questions to ask suppliers about sustainability.

Herbal Medicines are often extremely safe to take, however it is important to buy herbal medicines from a reputed supplier. Sometimes herbs bought from unreputable sources are contaminated, adulterated or substituted with incorrect plant matter.

Some important markers for quality to look for would be to look for certified organic labelling, ensuring that the correct scientific/botanical name is used and that suppliers can provide information about the source of ingredients used in the product. 

A supplier should be able to tell you where the herbs have come from. There is more space for contamination and adulteration when the supply chain is unknown.

Slippery elm tree is easy to grow. The seeds (samaras) which are similar to the helicopter sycamore seeds can be gathered in spring when they are full ripe and fall from the tree. Slippery elm is most suitable for arid areas, due to its drought-resistance. It requires a moderately sunny to full sun position in order to thrive. Good drainage is important for successful growing of this beautiful tree.

• The seeds need to be air dried, which usually takes a week. The seeds then need to be stratified at around 5°C in a moist medium for between 60- 90 days before planting.
• Seedlings will sprout in a moist rich soil after having undergone the above process.
• Once they reach around 8- 10 cm tall with 2 – 3 sets of leaflets they can be transplanted into a large pot of container, or directly out into the garden.
• Overall, once established this tree will be able to absorb all the water it needs by its self.

1. United Plant Savers. (n.d.). Slippery Elm – Ulmus rubra. [online] Available at: https://unitedplantsavers.org/species-at-risk-list/slippery-elm-ulmus-rubra/.
2. Menzies-Trull, C. (2013). Herbal medicine keys to physiomedicalism including pharmacopoeia. Newcastle: Faculty Of Physiomedical Herbal Medicine (Fphm).
3. Wood. M. 2004. The Practice of Traditional Western Herbalism: Basic Organs and Systems. North Atlantic Books,U.S.
4. Hoffman, D. (2003). Medical Herbalism: The Science Principles and Practices Of Herbal Medicine. Hardback (1st Edition). Independently published.
5. Clinical Advisor (2016). Slippery elm: an effective anti-inflammatory agent – Clinical Advisor. [online] Clinical Advisor. Available at: https://www.clinicaladvisor.com/home/features/alternative-meds-update/slippery-elm-an-effective-anti-inflammatory-agent/.
6. Langmead, L., Dawson, C., Hawkins, C., Banna, N., Loo, S. and Rampton, D.S. (2002). Antioxidant effects of herbal therapies used by patients with inflammatory bowel disease: an in vitro study. Alimentary Pharmacology and Therapeutics, 16(2), pp.197–205. doi:10.1046/j.1365-2036.2002.01157.x.
7. Hawrelak, J.A. and Myers, S.P. (2010). Effects of Two Natural Medicine Formulations on Irritable Bowel Syndrome Symptoms: A Pilot Study. The Journal of Alternative and Complementary Medicine, 16(10), pp.1065–1071. doi:10.1089/acm.2009.0090.
8. ResearchGate. (n.d.). (PDF) Slippery Elm, its Biochemistry, and use as a Complementary and Alternative Treatment for Laryngeal Irritation. [online] Available at: https://www.researchgate.net/publication/265058434_Slippery_Elm_its_Biochemistry_and_use_as_a_Complementary_and_Alternative_Treatment_for_Laryngeal_Irritation.