Labrador Tea Benefits, Preparation, and Safety Tips

Labrador tea is a wild herbal tisane brewed from the leaves of several closely related evergreen shrubs that grow across northern North America, Scandinavia, and Russia. It has a long history of medicinal use among Indigenous peoples, and modern research has begun to back up some of those traditional applications, particularly around inflammation, antioxidant activity, and blood sugar regulation. But Labrador tea also carries real safety risks that anyone brewing it should understand before their first cup.

What Labrador Tea Actually Is

The name “Labrador tea” does not refer to a single plant. It covers a group of eight evergreen shrub species belonging to the subdivision Rhododendron subsect. Ledum, found in temperate and subarctic regions of the Northern Hemisphere.¹ The two species most commonly used for tea are Rhododendron groenlandicum (Bog Labrador tea), which is widespread across Canada and the northern United States, and Rhododendron tomentosum (Northern Labrador tea or “Tundra tea”), found across northern Canada, Greenland, Alaska, and into Scandinavia.²

These shrubs share some easy-to-spot features. They are low-growing, typically reaching knee height or a bit taller. The leaves are leathery, narrow, and evergreen, with edges that curl under. The underside of the leaves is covered in a distinctive fuzz that ranges from white to rust-colored depending on the species and leaf age. When crushed, the leaves release a strong, resinous, conifer-like aroma from their essential oils.³ They grow in acidic, boggy, and peaty soils, the kind of wet, mossy ground you find in boreal forests and tundra.

A Deep Tradition of Medicinal Use

Labrador tea is among the most prominent medicinal plants in the traditions of Inuit, Cree, and other First Nations peoples of Northern Canada, Greenland, and Alaska. Indigenous communities have used it to treat more than 40 different ailments, including toothaches, respiratory disease, diabetes, infections, swelling, and rheumatism.² The leaves are the most commonly used part, although young shoots serve similar purposes. People drink it as a brewed tea, and it is also applied topically to treat toothaches and skin sores.

These are not just historical practices. Communities in northern Canada still use Labrador tea regularly for its medicinal properties. European settlers and fur traders also adopted the beverage, using it as a substitute when imported tea was scarce. That history of cross-cultural adoption speaks to how noticeable the plant’s effects are, even anecdotally. The breadth of traditional applications is striking, and it has made Labrador tea a priority for researchers trying to identify which of those uses hold up under controlled testing.

Antioxidant and Anti-Inflammatory Effects

The most consistently supported benefits in modern research involve antioxidant and anti-inflammatory activity. Extracts from R. tomentosum have been shown to decrease production of TNFα, a key pro-inflammatory signaling molecule, in laboratory immune-cell models. The antioxidant effect has been confirmed through free-radical scavenging assays, and researchers attribute both properties largely to the polyphenol content of the leaves, including catechin and various quercetin derivatives.²

Work on the closely related R. groenlandicum has found similar results. Twig extracts inhibited nitric oxide release by about 28 percent, and leaf extracts by about 17 percent, at the same concentration as a standard pharmaceutical nitric oxide inhibitor, which reduced release by 24 percent.⁴ In plain terms, the leaf and twig extracts performed in the same ballpark as a synthetic comparison compound in cell-based inflammation tests. The twig extract actually outperformed it slightly.

It is worth being clear about what this does and does not mean. These are lab studies on isolated cells, not clinical trials in people. They show that the plant contains compounds with genuine biological activity against inflammation and oxidative stress, which lines up well with the traditional uses for pain, infection, and swelling. But jumping from “it reduces inflammation markers in a petri dish” to “drinking the tea will meaningfully reduce your joint pain” requires evidence that has not yet been produced in human trials. The direction is encouraging, but the distance between lab bench and kitchen table is large.

Blood Sugar and Metabolic Research

One of the more intriguing lines of Labrador tea research involves its effects on blood sugar and insulin, an area where the Cree of Eastern James Bay have long used the plant as a traditional treatment for diabetes. In a study using diet-induced obese mice, Labrador tea extract lowered blood glucose by about 13 percent and improved the response to a glucose tolerance test by roughly 18 percent. Plasma insulin dropped by about 65 percent, suggesting the animals were becoming less insulin-resistant rather than just producing more insulin to compensate. The treatment also cut liver triglyceride accumulation by about 42 percent, meaning it helped prevent fatty liver, a common consequence of metabolic dysfunction.⁵

Follow-up research on the same mouse model found that the extract also improved markers of kidney health, another organ commonly damaged by insulin resistance and obesity.⁶ The mechanism appears to involve activation of cellular signaling pathways that help muscles take up glucose more efficiently.

These are animal studies, so the same caution applies: we do not yet know whether drinking Labrador tea in normal amounts produces comparable metabolic benefits in humans. The mouse doses were controlled extracts, not a cup of brewed tea. Still, the convergence between the traditional Cree use of this plant for diabetes and the laboratory findings that it improves insulin sensitivity in an animal model of metabolic disease is more than coincidental. It suggests the traditional knowledge identified a real pharmacological effect, even if the precise dose-response relationship in humans remains undefined.

How to Prepare Labrador Tea

Brewing Labrador tea is simple but does require some attention to quantity. The standard recipe calls for one teaspoonful of dried leaves per cup of boiling water, steeped for about five minutes.³ Longer steeping times will produce a stronger, more resinous flavor, but they also increase the extraction of compounds that can cause problems in higher concentrations, a point covered in the safety section below.

If you are working with fresh leaves rather than dried, you can use a somewhat larger amount since fresh leaves contain water weight. Older leaves, the ones lower on the stem with the most pronounced rusty fuzz underneath, are traditionally preferred. The essential oils in the leaves give the brew a distinctive piney, slightly sweet aroma and a flavor that people often compare to a cross between rosemary and spruce tips. The plant is also a natural source of vitamin C, which historically made it valuable in northern regions where fresh fruit was scarce during winter months.³

To dry your own leaves, spread freshly picked leaves in a single layer on a screen or clean cloth in a warm, well-ventilated area out of direct sunlight. They are ready when they feel crisp and crumble easily, typically after a few days. Store dried leaves in an airtight container away from light and heat, where they will keep their potency for months.

Safety Risks You Should Know About

Labrador tea contains two compounds that make overconsumption genuinely dangerous: ledol and grayanotoxins. These are the reason the traditional recommendation has always been to drink Labrador tea in moderation. The standard safety advice, reflected in published reviews, is to limit consumption to no more than one cup per day.³

Ledol is a sesquiterpene found in the essential oil of the leaves. In large amounts it acts as a nervous system irritant and can cause headaches, nausea, cramps, and in severe cases, paralysis or loss of consciousness. Grayanotoxins are a separate class of toxins found across many plants in the Rhododendron family. They interfere with sodium channels in nerve and muscle cells, and poisoning symptoms include dizziness, weakness, excessive sweating, nausea, and dangerously low blood pressure or slow heart rate. Grayanotoxin poisoning from honey made by bees foraging on rhododendrons (so-called “mad honey”) has been documented for centuries in other parts of the world, and the same toxin class is present in Labrador tea leaves.

The practical upshot is straightforward: one weak to moderate cup per day, brewed for five minutes or less, is the traditional safe range. Do not boil the leaves for an extended period, as this concentrates the toxic compounds. Do not drink multiple cups in a sitting. And pregnant or breastfeeding individuals should avoid it entirely, since the effects of ledol and grayanotoxins on fetal development are not studied.

Misidentification Is a Real Danger

If you forage Labrador tea yourself, correct identification is not optional. Several other plants share its boggy habitat and have a superficially similar appearance, and some of those look-alikes are considerably more toxic. The single most important identification feature is the leaf underside: true Labrador tea leaves have a dense, woolly layer of hairs, white on young leaves and aging to a rusty orange-brown. The leaf margins curl distinctly downward. The plant produces clusters of small white flowers in late spring and early summer.

Before harvesting any wild plant for consumption, cross-reference multiple identification features, not just one. Leaf shape alone is not sufficient. If you are new to foraging in boreal environments, going out with someone experienced the first few times is the safest approach. Field guides specific to your region are far more useful than general wildflower references, since the relevant look-alikes vary by geography.

Sustainable Harvesting Practices

Because Labrador tea grows slowly in nutrient-poor environments, how you harvest matters for the plant’s survival. Research on the effects of leaf harvesting on R. groenlandicum found that removing all leaves from a plant had a clearly negative impact. Stem growth slowed after the first full harvest, and after a second round of complete leaf removal, leaf production and stem growth dropped further. Two-thirds of the plants that were stripped of all their leaves twice died.⁷

The good news is that the same study found harvesting only older leaves had no significant impact on growth, leaf production, or survival, even after two consecutive years. This aligns with traditional harvesting practices, which have long favored picking the older, lower leaves and leaving the younger growth at the branch tips intact. If you follow this approach, you can gather Labrador tea sustainably without damaging the population you depend on.

A sensible rule of thumb: never take more than a third of the leaves from any single plant, and stick to the older leaves. Move through a patch rather than stripping individual shrubs. Labrador tea patches can be extensive, covering large areas of bog and muskeg, so spreading your harvest across many plants is easy and ensures each one recovers fully.

Beyond the Cup

Labrador tea’s uses extend past the beverage. The essential oil extracted from the leaves has attracted interest in aromatherapy, where it is sometimes marketed for respiratory support and relaxation, though clinical evidence for inhaled essential oil benefits remains thin across the board regardless of the plant source. In northern cooking traditions, the dried leaves are occasionally used as a spice, adding a piney, herbaceous note to game meats, stews, and smoked foods. Some craft brewers in Canada have experimented with adding it to beer, drawing on early colonial recipes that used the plant as a bittering agent before hops became universally available.

Researchers have also investigated Labrador tea extracts for potential anticancer activity. Early-stage laboratory work has examined their effects on leukemia cells, though this research is still in the cell-culture phase and far from any clinical application.² The breadth of the plant’s phytochemical profile, which includes dozens of identified compounds across multiple classes of bioactive molecules, means there are still plenty of potential applications that have not been tested at all.¹ For now, the most honest summary is that Labrador tea is a plant whose traditional reputation is earning increasing scientific respect, but whose therapeutic boundaries in humans remain largely uncharted.