Labrador tea

Scientific Name(s): Ledum groelandicum Oeder Ericaceae, Ledum latifolium Jacq., Ledum palustre L. ssp groelandicum Nutt. Ericaceae 1 , 2

Common Name(s): Swamp tea , Hudson's Bay tea , muskeg tea , Indian tea , Labrador tea , James tea , marsh tea , Haida tea 1 , 2

Uses

Labrador tea has been used historically and in folk medicine for a variety of ailments, including skin complaints, colds, and malignancies. However, clinical trials to support uses of Labrador tea are lacking.

Dosing

There is no clinical evidence to support specific dosage recommendations for Labrador tea. It can be made safely into a weak tea, but concentrations should not be too high. A tea for coughs, colds, bronchial infections, and pulmonary infections can be made by adding 1 teaspoonful of dried leaves to 1 cup of boiling water.

Contraindications

Contraindications have not been identified.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

Research reveals little or no information regarding adverse reactions with the use of this product.

Toxicology

Labrador tea has narcotic properties. If taken in concentrations that are too high, it can cause symptoms of intoxication that can lead to paralysis and death. If Labrador tea should be consumed, take only in small doses with weak concentrations.

Botany

L. groenlandicum is a short (50 to 200 cm), aromatic, evergreen shrub, primarily found in patches in Alaska, Greenland, and Canada, where it thrives in wet, peaty soils. It has bright green, 2.5 to 7.6 cm alternate oblong leaves with a leathery adaxial surface. The leaves are rolled and have a bluntly pointed tip. Younger leaves point upwards with a white, pubescent abaxial surface, while older reddish leaves point downwards and have a rust colored abaxial side. The small (12 mm), white, bell-shaped, scented flowers grow from slender stalks in dense terminal clusters. The fruit is a many-seeded brown woody capsule. 1 , 3 , 4 The species Ledum glanduosum Nutt. Ericaceae is not found on the coasts or mid-elevations compared with L. groelandicum , which is more widespread.

History

“Labrador tea” is named after the swamps of Greenland and Labrador, where it grows in profusion. The name is probably derived from the Hudson Bay traders who sold the leaves for tea. Prior to that, the Haida people used it as a medicine. 2

During the American Revolution, it was one of several herbs used as a pleasant-tasting substitute for commercial tea. In Germany, leaves were added to beer to make it more intoxicating.

The Haida people picked the leaves before the shrubs would flower or in late summer, dry them, and boil the leaves for tea. 2

Although the plant is found as far south as Wisconsin and Pennsylvania, it is considered to be rare and could become an endangered species. Labrador tea has been used in folk medicine for coughs, chest and kidney ailments, headache, rheumatism, diarrhea, sore throat, and malignancies. 3 , 4 , 5

Chemistry

Reported constituents of L. latifolium include tannic acid, arbutin, resin, and mineral salts. 3 Leaves contain 0.3% to 2.5% volatile oil, including the sesquiterpenes ledol and palustrol (ledum camphor), with valeric and other volatile acids, ericolin, and ericinol. 5

Uses and Pharmacology

The leaves of L. groenlandicum have been used as an astringent. They were once used to treat dysentery and diarrhea. 3 They are also said to be very useful in coughs and colds, as well as bronchial and pulmonary infections. The tea is prepared by adding 1 teaspoonful of dried leaves to 1 cup of boiling water.

A stronger decoction has been recommended externally for itching and redness from skin ailments, such as poison ivy. The leaves as a tea have also been used as a heart medicine, and for indigestion, diarrhea, and ease of childbirth. 1 , 4 Homeopathy has used Labrador tea for various ailments, such as insect bites and stings, acne, prickly heat, varicella, and wounds. Homeopathic use also includes asthma, hand and foot pain, gout, rheumatism, ear inflammation, tinnitus, and tuberculosis. 4 Other research discusses use of the leaves in Korea to treat female disorders. 6 It is rarely used today for its historical uses. 3

Dosage

There is no clinical evidence to support specific dosage recommendations for Labrador tea. However, concentrations should not be too high.

Recorded recommendations are 1 teaspoonful of dried leaves for 1 cup of boiling water.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

Research reveals no information regarding adverse reactions of Ledum .

Toxicology

Labrador tea has narcotic properties. Evidence suggests that excessive use of the tea may cause delirium or poisoning. 3 Toxic terpenes of the essential oils cause symptoms of intoxication, such as slow pulse, lowering of blood pressure, lack of coordination, convulsions, paralysis, and death. 6 It is apparently safe in a weak tea solution, but should not be made too strong. 1 , 7

There are 2 other plants that are similar to Ledum and can be toxic due to higher concentrations of similar compounds: Kalmia polifolia and Andromeda polifolia . These are distinguished by their glabrous leaves and pink flowers. 1

Bibliography

1. Turner, NJ. Food Plants of Interior First Peoples . Royal British Columbia Museum Handbook. Vancouver, BC, Canada: UBC Press; 1997.
2. Turner, NJ. Plants of Haida Gwaii . Winlaw, BC, Canada: Sono Nis Press; 2005:156.
3. Stuart M, ed. The Encyclopedia of Herbs and Herbalism . New York, NY: Crescent Books; 1987:213.
4. Hutchens AR. Indian Herbalogy of North America . Boston, MA: Shambhala Publications; 1991:172-173.
5. Duke JA. CRC Handbook of Medicinal Herbs . Boca Raton, FL: CRC Press Inc; 1985:275.
6. Belleau F, Collin G. Composition of the essential oil of Ledum groenlandicum . Phytochemistry . 1993;33(1):117-121. doi:10.1016/0031-9422(93)85406-H.
7. Turner NJ, et al. Common Poisonous Plants and Mushrooms of North America . Portland, OR: Timber Press;1991:267.

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