Graham Butler, BSc, CNPA, RH
Slippery elm bark's benefits were discovered by First Nations' herbalists long ago. Today it's used to relieve colds, coughs, and digestive disorders.
The small-leaved elm (Ulmus rubra and Ulmus fulva) is indigenous to the moist woodlands of eastern North America. Although similar species grow in Europe and were used to a limited degree by ancient Greek physicians, slippery elm is closely identified with Native American herbalism.
Traditionally, the sticky, mucilage-rich inner bark (the medicinal portion of the plant) was dried, then ground and prepared as a salve for burns and wounds and as a base for poultices. First Nations herbalists long ago discovered that the mucilage had a soothing effect on skin and mucous membranes. It was also used in preparations for colds, sore throats, coughs, and digestive disorders. When starvation loomed, slippery elm bark could even be used as a survival food, chopped or ground and boiled much like oatmeal. European settlers called the tree Indian elm and quickly adopted the herb. Its use was well established by the 1600s.
Slippery elm was included in the US Pharmacopeia from 1820 to 1960, based largely on its historical use in soothing skin and digestive irritations and as a cough suppressant. Throat lozenges are still one of the most common forms of the herb.
Never Make Assumptions
Slippery elm bark is composed of a complex mixture of polysaccharides that form a soothing gelatinous fibre or mucilage. The bark contains about 3 percent tannins, which have a primarily astringent action that protects skin and mucous membranes from infection and irritation. The bark also contains high concentrations of antioxidants, including phytosterols and flavonoids.
Surprisingly, the research community has largely ignored this rather useful herb, likely because it has always been assumed that its healing character is due wholly to the soothing and protective character of its mucilage. This assumption may have been somewhat premature. A relatively recent British study published in Alimentary Pharmacology and Therapeutics in 2002 examined the relationship between damaging free radicals produced by gastrointestinal inflammation and the free-radical scavenging activity of several herbs, including slippery elm bark. The study concluded that slippery elm had the potential to significantly reduce intestinal inflammation associated with diseases such as ulcerative colitis and Crohn’s disease, and was worthy of further study. Results of a Korean study published in Phytotherapy Research later the same year supported the British findings.
Slippery elm is used in many herbal traditions, including traditional Western, Ayurvedic, and traditional Chinese medicine, well beyond its Native American origins and a tribute to its utility.
Slippery elm has a long history as a first aid and home remedy. Capsules, teas, and lozenges are useful to relieve symptoms associated with throat and digestive irritation. All are generally safe for adults and older children, although serious or recurring complaints should be diagnosed by a qualified practitioner. Young children may gag on the sticky tea and infusion.
Although no known dangers are associated with the use of slippery elm, a few cautions are advisable. Mucilage, which is a soluble fibre, can interfere with the absorption of prescription medications. Always take prescription medications separately. The bark has a bulking effect; therefore, always consume it with plenty of liquid. In addition, slippery elm should be avoided in cases of bowel obstruction or blockage.
Slippery Elm Tea
Prepare an infusion of 2 Tbsp (30 mL) of slippery elm powder in 2 cups (500 mL) of boiling water and steep for three to five minutes. Take two to three times daily to soothe digestive upset or irritation.