Labrador Tea (Rhododendron groenlandicum): Benefits, Dosage, Safety & Evidence

Frequently asked questions

How does Labrador tea work as an expectorant?

Labrador tea acts as an expectorant due to its content of volatile oils, specifically ledol and palustrol. These compounds help loosen bronchial secretions, facilitating the clearance of mucus from the respiratory tract. Traditionally used by First Nations peoples for coughs and colds, the herb also contains flavonoids that may contribute to anti-inflammatory effects. However, clinical trials confirming these specific mechanisms in humans are lacking (Evidence Level: C).

Is Labrador tea safe to drink during pregnancy?

No, Labrador tea is considered unsafe during pregnancy. The plant contains volatile oils, including ledol, which may stimulate uterine contractions or cause toxicity to the developing fetus. Due to these potential risks and the lack of safety data, pregnant and breastfeeding women should strictly avoid consuming this herb. Safer alternatives for respiratory or digestive issues should be discussed with a qualified healthcare provider (Evidence Level: C).

What is the recommended dosage for Labrador tea?

The traditional adult dosage is 1-2 grams of dried leaves steeped in hot water for 5-10 minutes, consumed twice daily. It is critical to prepare this as a dilute tea rather than a concentrated extract. High concentrations of the active compound ledol can be toxic, causing adverse effects like drowsiness or gastric distress. Adhering strictly to traditional infusion methods is essential for safety (Evidence Level: Traditional).

Does Labrador tea interact with sedatives or other medications?

Yes, Labrador tea may interact with central nervous system (CNS) depressants. Because the herb can cause drowsiness, taking it alongside sedatives, tranquilizers, or alcohol may potentiate these effects, leading to excessive sedation. Furthermore, because the herb contains toxic compounds in high doses, combining it with drugs that affect liver metabolism could theoretically increase the risk of toxicity. Medical supervision is advised for those on prescription medications (Evidence Level: C).

What is Labrador tea used for medicinally?

Labrador tea is traditionally used by First Nations peoples across Canada and Alaska to treat respiratory conditions, such as coughs, colds, and chest congestion. It functions as an expectorant and is also employed for digestive issues, worm infestations, and headache relief. While these uses are well-documented in ethnobotanical records, scientific validation remains limited, and users must exercise caution regarding preparation methods to avoid toxicity (Evidence Level: C).

PubMed-compiled information sheet

This sheet was compiled from PubMed (NIH) abstracts using AI assistance. Every factual claim is cited to a real PubMed article (see the source list). It has not yet been human-reviewed — confirm with a healthcare provider before use.

Compiled from 30 PubMed articles · model: gemma4:31b

Summary

Labrador tea (Rhododendron groenlandicum) is a medicinal plant used by Indigenous peoples in North America, demonstrating potential antidiabetic and renoprotective effects in animal models [PMID:26916332, PMID:25916863].

Background

Labrador tea refers to the dried leaves of species such as Rhododendron groenlandicum, R. tomentosum, or R. neoglandulosum [PMID:25156477]. It is an evergreen shrub found in temperate and subarctic regions of the Northern Hemisphere [PMID:38592945].

Traditional uses

Used by the Cree Nations of northern Quebec and other First Nations communities as a beverage and medicinal tea [PMID:25916863, PMID:32113170]. It has been used in Native American traditional medicine to treat inflammatory pathologies including asthma, rheumatisms, and burns [PMID:17156957], and by indigenous peoples in Alaska, Canada, and Greenland for a diversity of ailments [PMID:29701283].

Active compounds

The plant contains essential oils, flavonoids, phenolic acids, and terpenoids [PMID:38592945]. Specific identified compounds include (+)-catechin, (-)-epicatechin, quercetin [PMID:26707751, PMID:39877830], ursolic acid [PMID:39877830, PMID:29701283], and germacrone, which is a major component of its essential oil [PMID:24263998]. It is also a source of ascorbic acid [PMID:25156477].

Mechanism of action

In diet-induced obesity mouse models, Labrador tea stimulated the insulin-dependent Akt pathway [PMID:25916863]. In vitro, it has shown glitazone-like activity in 3T3-L1 adipogenesis bioassays [PMID:26707751, PMID:26508979].

Clinical evidence

Evidence DDiabetes/Insulin Resistance

In a diet-induced obesity mouse model, extract significantly reduced blood glucose (13%), plasma insulin (65%), and the response to an oral glucose tolerance test (18.2%), while preventing hepatic steatosis [PMID:25916863].

Evidence DRenal Integrity

In diet-induced obese mice, the plant extract showed a tendency to improve microalbuminuria and renal fibrosis [PMID:26916332].

Evidence DInflammation

Methanol extracts of leaves and twigs inhibited nitric oxide (NO) release in LPS-stimulated RAW 264.7 macrophages [PMID:17156957].

Evidence DOral Bacteria (F. nucleatum)

Essential oils showed antibacterial activity and decreased bacterial viability in pre-formed biofilms [PMID:33182686].

Safety & adverse effects

The beverage should not be consumed more than once daily due to the toxicity of ledol and grayanotoxin [PMID:25156477].

Drug interactions

Decoctions of Rhododendron groenlandicum may have the potential to inhibit cytochrome P450 3A4 (CYP3A4)-mediated metabolism, with inhibition increasing the longer the leaves are brewed [PMID:24971793].

Dosage & administration

A common recipe involves adding one teaspoonful of dried leaves to one cup of boiling water and brewing for 5 minutes [PMID:25156477]. Consult a healthcare provider.

Evidence summary

The current evidence is primarily based on in vitro studies and animal models (Level D), with some review-level data (Level C) regarding traditional use and phytochemistry. No human clinical trials were provided.

PubMed sources

1.PMID: 26916332 (2016) — Rhododendron groenlandicum (Labrador tea), an antidiabetic plant from the traditional pharmacopoeia of the Canadian Eastern James Bay Cree, improves renal integrity in the diet-induced obese mouse model. · Pharmaceutical biology
2.PMID: 25916863 (2016) — Labrador tea (Rhododendron groenlandicum) attenuates insulin resistance in a diet-induced obesity mouse model. · European journal of nutrition
3.PMID: 26707751 (2016) — A combination of (+)-catechin and (-)-epicatechin underlies the in vitro adipogenic action of Labrador tea (Rhododendron groenlandicum), an antidiabetic medicinal plant of the Eastern James Bay Cree pharmacopeia. · Journal of ethnopharmacology
4.PMID: 25156477 (2015) — Labrador tea--the aromatic beverage and spice: a review of origin, processing and safety. · Journal of the science of food and agriculture
5.PMID: 32113170

Labrador Tea

Sources & Citations

Calculate a safe dose of Labrador Tea

Costmary

Crescentia Cujete

Cleome Gynandra

Frequently asked questions

Summary

Background

Traditional uses

Active compounds

Mechanism of action

Clinical evidence

Safety & adverse effects

Drug interactions

Dosage & administration

Evidence summary

PubMed sources

Government sources

Labrador Tea

Sources & Citations

Calculate a safe dose of Labrador Tea

Related Herbs

Costmary

Crescentia Cujete

Cleome Gynandra

Frequently asked questions

Summary

Background

Traditional uses

Active compounds

Mechanism of action

Clinical evidence

Safety & adverse effects

Drug interactions

Dosage & administration

Evidence summary

PubMed sources

Government sources