General Description
Slippery elm (also known as red elm, moose elm, Indian elm, gray
elm, or soft elm) is a deciduous tree native to the eastern half
of the United States and adjacent areas of southern Canada. Growing
up to 40 meters in height, slippery elm has alternate, elliptical,
doubly serrated leaves, which are dark, glossy green on top and
paler and slightly fuzzy underneath. Slippery elm flowers from March
to May, bearing small, bright red clusters shortly before the leaves
open. The fruit, which matures from May to June, shortly after the
leaves appear, is flat and almost disc-shaped, measuring roughly
15 mm in diameter. The tree has a thick, dark, reddish-brown outer
bark, which may be deeply furrowed, and a whitish, mucilage-rich
inner bark, which is used medicinally.
Health applications
- Cough/sore throat
- Common cold
- Indigestion
- Heartburn
History and traditional use
Slippery elm bark was used extensively by Native American tribes
for a variety of medicinal and other purposes. Tribes in the Missouri
River valley used a decoction of the inner bark to make a soothing
laxative. The Omahas rendered buffalo fat with slippery elm bark
to add flavor and prevent rancidity. The Osage used slippery elm
bark in poultices to aid wound healing.1 Herbalists
continue to value the herb for its ability to soothe mucous membranes,
commonly recommending it to treat coughs, sore throats, and gastrointestinal
irritations.2 A common ingredient in cough drops,
slippery elm is one of the few medicinal plants approved as an over-the-counter
(OTC) drug by the FDA,1 having long held official
status in The United States Pharmacopeia and The National Formulary.3
Chemical composition
Slippery elm bark contains a mucilage composed of various sugars,
including pentosans, methyl pentosans, and hexosan, which has
a soothing effect on mucous membranes.4
Conventional Use
Modern use of slippery elm bark is very much in keeping with traditional
applications, including coughs, sore throat, and stomach irritations
such as heartburn, indigestion, and ulcers.5-8
Although the soothing properties of slippery elm bark have long
been well known, there has been little scientific study investigating
the herb's effectiveness.
Dosage/toxicity
Recommended dosages for slippery elm vary widely with intended
use and form of delivery (i.e. teas, lozenges, tinctures, or capsules).
Most slippery elm products have dosage recommendations printed
on the labelling. Slippery elm bark appears to be very safe, and
there are no known health hazards or side effects associated with
proper administration of designated therapeutic dosages.4
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