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Omnia Sana · Plant Monograph

Labrador-tea

Rhododendron tomentosum

Family EricaceaeParts used Leaf, StemAlso known as Labrador tea, bog tea, Hudson's Bay tea, marsh tea

This monograph compiles 3 pharmacological actions, 7 traditional / indicated uses, supported by 13 cited sources, drawn directly from the Omnia Sana plant database.

Pharmacological Actions

Anti-inflammatory[1, 2, 3, 4, 11, 12, 13]
Antioxidant[1, 4, 12, 13]
Diuretic[1, 12, 13]

Traditional & Indicated Uses

Arthritis / joint pain[1, 2, 11, 12, 13]Traditional · 2/10

inferred from anti-inflammatory action

more plants for arthritis / joint pain →detailed sources →
Inflammation (general)[1, 12, 13]Traditional · 1/10

inferred from anti-inflammatory action

more plants for inflammation (general) →detailed sources →
Respiratory support[1, 6, 12, 13]Traditional · 1/10
more plants for respiratory support →detailed sources →
Skin irritation[1, 12, 13]Traditional · 1/10

inferred from anti-inflammatory action

more plants for skin irritation →detailed sources →
Swelling / fluid retention[1, 3, 11, 12, 13]Limited · 3/10

inferred from diuretic action

more plants for swelling / fluid retention →detailed sources →
Urinary support[1, 12, 13]Traditional · 1/10

inferred from diuretic action

more plants for urinary support →detailed sources →
Urinary tract infection (UTI)[1, 12, 13]Traditional · 1/10

inferred from diuretic action

more plants for urinary tract infection (uti) →detailed sources →

Safety, Cautions & Contraindications

Safety note[1, 12, 13]Caution

Labrador tea contains ledol, a toxic sesquiterpene alcohol, particularly concentrated in fresh leaves. Excessive consumption can cause dizziness, headache, nausea, and even toxicity (especially in the related Ledum palustre). Use only in small, controlled amounts. Not recommended during pregnancy or breastfeeding. Identify plant correctly — confusion with other bog plants can be dangerous.

Safety note[1, 12, 13]Caution

Duke (2002) rates Labrador tea as + (caution warranted) and notes primarily folkloric activities, with the plant acting as a diuretic, expectorant, and vulnerary. Importantly, Duke classifies it as having narcotic and deliriant potential — large doses can cause intoxication, hallucinations, and toxicity. It contains ericolin and ledol, which are potentially neurotoxic compounds. Duke emphasizes that Labrador tea should be used only with caution and at low doses, and notes that it is not appropriate for regular internal use given its toxicity profile at higher amounts (Duke, 2002).

References

REF-0053, REF-0880, REF-0881, REF-0882, REF-0883, REF-0884, REF-0885, REF-0886, REF-0887, REF-0888, REF-0889

References & Sources

  1. Dampc, A. and Luczkiewicz, M (2013) 'Rhododendron tomentosum (Ledum palustre): a review of traditional use based on current research', pp. 130--143. Traditional / reference
    Find this source
  2. Jesionek, A., Kokotkiewicz, A., Mikosik-Roczynska, A., Ciesielska-Figlon, K. and others (2019) 'Chemical variability of Rhododendron tomentosum (Ledum palustre) essential oils and their pro-apoptotic effect on lymphocytes and rheumatoid arthritis synoviocytes', Fitoterapia, 139, pp. 104402. doi:10.1016/j.fitote.2019.104402 Preclinical
    https://doi.org/10.1016/j.fitote.2019.104402
  3. Kang, J.Y., Tran, K.D., Seiff, S.R., Mack, W.P. and Lee, W.W (2017) 'Assessing the Effectiveness of Arnica montana and Rhododendron tomentosum (Ledum palustre) in the Reduction of Ecchymosis and Edema After Oculofacial Surgery: Preliminary Results', Ophthalmic Plastic and Reconstructive Surgery, 33(1), pp. 47-52. doi:10.1097/IOP.0000000000000645 Clinical study
    https://doi.org/10.1097/IOP.0000000000000645
  4. Vengryte, M. and Raudone, L (2024) 'Phytochemical Profiling and Biological Activities of Rhododendron subsect. Ledum: Discovering the Medicinal Potential of Labrador Tea Species in the Northern Hemisphere', Plants (Basel), 13(6), pp. 901. doi:10.3390/plants13060901 Traditional / reference
    https://doi.org/10.3390/plants13060901
  5. Iunusova, D.R., Polezhaeva, M.A. and Marchuk, E.A (2024) 'Confusing boundaries of the Labrador tea species: dispersal history explains the lack of clear species structure', Annals of Botany, 134(6), pp. 959-974. doi:10.1093/aob/mcae130 Preclinical
    https://doi.org/10.1093/aob/mcae130
  6. Dampc, A. and Luczkiewicz, M (2014) 'Labrador tea - the aromatic beverage and spice: a review of origin, processing and safety', Journal of the Science of Food and Agriculture, 95(8), pp. 1577-1583. doi:10.1002/jsfa.6889 Traditional / reference
    https://doi.org/10.1002/jsfa.6889
  7. Jaenson, T.G.T., Palsson, K. and Borg-Karlson, A.K (2005) 'Evaluation of extracts and oils of tick-repellent plants from Sweden', Medical and Veterinary Entomology, 19(4), pp. 345-352. doi:10.1111/j.1365-2915.2005.00578.x Preclinical
    https://doi.org/10.1111/j.1365-2915.2005.00578.x
  8. Tattje, D.H.E. and Bos, R (1981) 'Composition of essential oil of Ledum palustre', Planta Medica, 41(3), pp. 303-307. doi:10.1055/s-2007-971719 Preclinical
    https://doi.org/10.1055/s-2007-971719
  9. Zhang, K., Wang, J., Chen, L., Li, J. and others (2019) 'Two new taraxerane-type triterpenes from Ledum palustre L', Natural Product Research, 34(19), pp. 2723-2728. doi:10.1080/14786419.2019.1586689 Preclinical
    https://doi.org/10.1080/14786419.2019.1586689
  10. Islam, M.N., Khalil, M.I., Islam, M.A. and Gan, S.H (2013) 'Toxic compounds in honey', Journal of Applied Toxicology, 34(7), pp. 733-742. doi:10.1002/jat.2952 Traditional / reference
    https://doi.org/10.1002/jat.2952
  11. Baananou, S., Bagdonaite, E., Marongiu, B., Piras, A. and others (2014) 'Supercritical CO2 extract and essential oil of aerial part of Ledum palustre L. - Chemical composition and anti-inflammatory activity', Natural Product Research, 29(11), pp. 999-1005. doi:10.1080/14786419.2014.965167 Preclinical
    https://doi.org/10.1080/14786419.2014.965167
  12. Grieve, M (1931) 'A Modern Herbal'. Traditional / reference
    Find this source
  13. Royal Botanic Gardens, Kew (n.d.). Available at: https://powo.science.kew.org Traditional / reference
    https://powo.science.kew.org

Record last updated 2026-06-20 · Provenance: book+pubmed · Status: verified

This fact sheet is generated automatically from the Omnia Sana plant database and reflects its latest synced data. It is provided for educational purposes only and is not medical advice. Always consult a qualified practitioner before using medicinal plants.

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