Tree lungwort

What is Tree lungwort?

Tree lungwort is a large, leafy, lettuce-like lichen that grows on the bark of old trees. It is not a plant. It is a fungus and an alga living together as one body.

It is called lungenever in Norway, lunglav in Sweden and raidankeuhkojäkälä in Finland. Scandinavian folk healers brewed it as a bitter tea for coughs and chest trouble. It was also used to flavour beer and to dye wool brown.

Here is the honest verdict. No human trials support any medical use of tree lungwort. Long traditional use is not proof that it works, and it is not proof that it is safe.

One more thing matters before you look for it. The lichen is rare and slow-growing, and it is protected in parts of Europe. Wild picking may be illegal where you live.

How does Tree lungwort work?

Nobody has shown how, or whether, tree lungwort acts on the human lung.

The original reason for using it was looks, not testing. Its pitted, ridged surface was thought to resemble lung tissue. This old idea is called the doctrine of signatures.

Lab work offers a few hints and nothing more. In test tubes, lichen acids from Lobaria species slow the growth of some bacteria and fungi. Whether that happens in a person's airway has never been shown.

In cell studies, some lichen compounds lower markers of inflammation (swelling and irritation). Those were isolated cells in a dish. The step from a dish to a human chest is a large one.

Its bitter taste was long thought to wake up appetite and digestion. Bitter herbs do trigger taste receptors in the mouth. Any real benefit from that, for tree lungwort, is untested.

What forms does Tree lungwort come in?

Tree lungwort is not a mainstream commercial product. You are most likely to meet it in these forms:

- Dried whole lichen, sold loose by wildcraft and specialist herb sellers. - Cut and sifted lichen, for a tea or a simmered decoction. - An alcohol tincture, made from the dried lichen.

Two other forms turn up less often:

- Powder in capsules, which is uncommon. - Sticta pulmonaria, a homeopathic product made from this lichen.

Homeopathic dilutions hold little or no starting material. They are not expected to act like the herb itself.

In the past it also went into beer as a bitter, and into dye pots for wool.

Quality control is poor across all of these. There is no standard strength, no agreed marker compound and little testing. Lichens also soak up metals and pollution from the air around them.

Where it comes from:

Tree lungwort held a steady place in northern European and Scandinavian folk medicine from at least the 1500s.

Early herbalists recommended it for coughs, hoarseness, chest tightness and spitting of blood. It was given as a bitter tea or boiled in milk or beer. Its use spread partly because its ridged surface was said to mirror the lung.

It had plain household jobs too. Scandinavian and Siberian brewers used it as a bitter in beer. Tanners used it on hides, and dyers used it for brown wool.

In hard years it was fed to livestock, and people ate it as famine food.

These records show that people used it widely and for a long time. They do not show that it helped anyone, because nobody measured that at the time.

What does Tree lungwort help with?

• Cough and chest congestion: This is the classic use, and the reason for the name. Scandinavian households brewed the dried lichen as a bitter tea for wet coughs. No trial has tested it for cough in people. A cough that lasts more than three weeks needs a doctor, not a lichen tea.
• Hoarseness and sore throat: Folk use included gargles and warm drinks for a rough voice. Any soothing feeling likely comes from the warm liquid itself. There is no human evidence that tree lungwort helps a sore throat or speeds healing.
• Asthma and long-term bronchitis (traditional claim only): Old herbals listed it for wheeze and long-standing chest illness. This claim is the riskiest one on the page. Asthma and COPD (a long-term lung disease) need proven inhaled medicines. Swapping them for a herb can be dangerous. No study supports tree lungwort for either condition.
• Poor appetite and weak digestion: The lichen is strongly bitter, and bitters were traditionally taken before meals. Bitter taste can prompt a normal digestive response. That general idea has not been tested with this lichen. Treat the claim as unproven.
• Washing minor wounds (historic use): Some accounts describe lichen washes on grazes and sores. In test tubes, lichen acids slow some bacteria. Whether that helps a real wound on skin has not been shown. Modern wound cleaning is safer and better studied.

What are the side effects of Tree lungwort?

• Nausea or stomach upset, especially from strong brews
• Loose stools or diarrhoea
• Bitter taste with mouth or throat irritation
• Itchy skin rash from handling the lichen (contact dermatitis)
• Allergic reactions, including swelling or trouble breathing (rare)
• Possible strain on the liver, based on concerns about lichen compounds in general

Good to know:

Reported side effects are few, but that reflects a lack of study rather than a clean record.

Stomach upset is the most likely problem. Skin rash is a known issue for people who handle lichens often.

The liver concern is a caution, not a confirmed finding for this species. Stop and get medical help if you notice yellow skin or eyes, dark urine, or pain under the right ribs.

How much Tree lungwort should you take?

• Recommended daily: There is no agreed amount for tree lungwort, and this page gives none as a personal instruction. No health authority has set a safe or useful dose. Products are rare, and labels vary a lot. Some dried-lichen teas list roughly 1 to 2 grams of lichen per cup. That figure only reflects what a label may carry. It is not advice, and no trial backs it. If you are considering this lichen at all, speak to a doctor or a trained herbalist first.
• Best time of day: Timing does not matter much, since no effect is proven. Bitter preparations were traditionally taken before meals for appetite. Cough teas were taken through the day and at bedtime. Neither pattern has been tested.
• With or without food: A little food in the stomach is the gentler option. The lichen is very bitter, and bitter teas can cause nausea on an empty stomach. Taking it with or just after food may reduce that. If you are using it as a digestive bitter, tradition placed it shortly before eating.
• Time to effect: Be prepared for it to do nothing measurable. No trial has measured any effect, so no honest time frame exists. A warm tea may feel soothing in the throat right away. That is the warm drink, not proof of a medicine at work. If symptoms are getting worse, do not wait and see.
• How long to take it: Tradition describes short, occasional use during a chest illness, not daily long-term use. No study has looked at what happens over weeks or months. Long use cannot be called safe, because it has never been checked. A cough lasting over three weeks, or any new breathlessness, is a reason to see a doctor rather than continue.