Labrador tea – the aromatic beverage and spice: a review of origin, processing and safety

Abstract

Labrador tea is a name for the dried leaves of Rhododendron groenlandicum, R. tomentosum or R. neoglandulosum (family Ericaceae, previously genus Ledum) as well as for the beverage native to North America, which is made from them. The above species are rich in the essential oil, which gives a conifer aroma to the tisane. Labrador tea is a valuable source of ascorbic acid, with tonic, improving digestion and relaxing activity. However, this beverage should not be drunk more than once daily because of the ledol and grayanotoxin toxicity. The common recipe for making Labrador tea is to add one teaspoonful of dried leaves to one cup of boiling water and to brew for 5 min. It is often sweetened or enriched with other flavors. Additionally, Labrador tea dried leaves are used to spice meat, soups, sauces, salads, beer, cakes and other dishes. In agriculture, its insecticidal properties can be useful for controlling pests.

Phytochemical Profiling and Biological Activities of Rhododendron Subsect. Ledum: Discovering the Medicinal Potential of Labrador Tea Species in the Northern Hemisphere

“…This problem first occurred when Ledum taxa were included in the genus Rhododendron in 1990 [ 1 ]. As the existing research shows, many authors to this day use old names for Ledum species plants: Rhododendron tomentosum as Ledum palustre , Rhododendron groenlandicum as Ledum latifolium or Ledum groenlandicum , and Rhododendron columbianum as Ledum glandulosum or neoglandulosum [ 6 , 11 ]. There are many different traditional names for Ledum species plants, such as Labrador tea, wild rosemary, marsh tea, and marsh rosemary.…”

“…Rhododendron subsect. Ledum species are one of the many evergreen plants, meaning that they retain their leaves throughout the year and into the following growing season [ 6 ]. Industrially, the leaves of evergreen plants are an intriguing raw material due to their availability throughout the growing season.…”

The book herbaria of Jacob Breyne (1637-1697) in the collection of Naturalis Biodiversity Center (Leiden, the Netherlands).

“…Breyne notes that the Swedish had imported 20 'voeder' (cartloads) of this plant from the 'Neering' (Frische Nehrung, Mierzeja Wiślana) to add to their soldiers' beer, 'because it makes for furiousness'. Leaves of R. tomentosum (known as Labrador Tea) are still used in the production of alcoholic beverages today, although its use has been banned in the past for causing aggressive behavior (Dampc & Luczkiewicz, 2015).…”

Risks for human health related to the presence of grayanotoxins in certain honey

“…Many Rhododendron species have been used in alternative medicine, and other ethnopharmacological applications e.g. traditional Chinese or Ayurvedic medicine (Popescu and Kopp, 2013 ; Dampc and Luczkiewicz, 2015 ; Shi et al., 2021 ). See also Annex B .…”