Iceland moss (poultice, wash, bath decoction)

What is Iceland moss (poultice, wash, bath decoction)?

Iceland moss is not a moss. It is a lichen, Cetraria islandica, that grows on open ground across Iceland, Norway, Sweden and Finland. This page covers the outside uses: a poultice (a soft mass held on the skin), a skin wash, and a bath made from the boiled plant.

The dried plant is grey-brown and curls into stiff, branching strips. Boiled in water, it gives off a thick, slippery gel. That gel is what northern households aimed at dry, rough or sore skin.

The honest verdict: there are no good human trials of Iceland moss used on skin. Long use in the north is not proof that it works. It is also not proof that it is safe.

The plant is better known as a tea or lozenge for a dry cough. Even that use rests on weak human evidence. Skin use rests on less.

How does Iceland moss (poultice, wash, bath decoction) work?

Most of the proposed action comes from the slime the plant makes in water, not from a drug-like effect.

Iceland moss is rich in mucilage (a plant slime). On skin, a slimy film may hold water in place and soften a dry patch. That is a plausible soothing effect, not a tested one.

In test tubes, lichen acids from this plant slow the growth of some bacteria. Whether that happens on human skin is not established.

Lab work also suggests the acids can calm some markers of inflammation (swelling and redness) in cell studies. No study has shown this in a person's skin.

Treat the mechanism as an idea, not a finding. A warm, wet compress alone soothes skin, and no trial has separated that from the plant itself.

What forms does Iceland moss (poultice, wash, bath decoction) come in?

For outside use, the plant is almost always bought as the loose dried lichen and brewed at home.

- Dried cut lichen, sold loose or in bulk packs. - Poultice: softened or boiled lichen, wrapped in clean cloth and laid on the skin. - Wash or compress: the strained brew, used cool or lukewarm on a cloth.

- Bath decoction (a strong boiled brew): the strained liquid, added to bath water. - Creams, salves and gels with Iceland moss extract. These are uncommon, and most mix it with other herbs.

Inside-the-body forms are sold far more widely. These include tea bags, syrups and lozenges for a dry cough or a sore throat. Those are a different use and are not covered here.

Where it comes from:

Iceland moss was a famine food and a household remedy across the Nordic countries for centuries. Icelanders called it fjallagrös and gathered it from the heath in summer. It was soaked, boiled in milk or water, and eaten as porridge or thick gruel.

Written records from the 1700s and 1800s list it for coughs, poor appetite and weak digestion. European pharmacy books of that era carried it as Lichen islandicus.

Outside use was household practice rather than formal medicine. Folk accounts describe the boiled plant laid warm on chapped hands, sores, boils and burns. The leftover brew was used as a wash, or poured into a bath for itchy or rough skin.

In Finland (islanninjäkälä) and Sweden (islandslav) similar uses were recorded. These accounts tell us what people did. They are not a reason to self-treat a wound today.

What does Iceland moss (poultice, wash, bath decoction) help with?

• Dry, rough or chapped skin: This is the most plausible use, and the weakest claim. The boiled plant leaves a slippery film that holds water on the skin. No trial has compared it with a plain moisturiser, so any gain over a basic cream is unknown.
• Mild skin irritation and itch: Nordic households used cool washes and compresses on itchy patches. Cell studies hint that lichen acids damp down some signs of inflammation (swelling and redness). That has not been shown on human skin, and a cool wet cloth soothes itch by itself.
• Cracked hands and heels: Farm and fishing households soaked hard, split skin in the warm brew. The idea was to soften the skin before work. There is no human evidence that it closes cracks faster than soaking in plain warm water.
• Minor grazes and shallow sores: Folk accounts describe poultices on small sores and boils. In test tubes, the lichen acids slow some bacteria. That does not mean the poultice cleans or heals a wound, and plant material on broken skin can carry dirt and germs into it.
• Soothing bath for rough or flaky skin: A strained bath brew was a common winter habit in Iceland and Finland. Readers describe it as softening. No study has measured skin condition before and after, so treat the comfort as real and the healing claim as untested.

Which foods are rich in Iceland moss (poultice, wash, bath decoction)?

Iceland moss is a wild food in its own right, not a nutrient found in other foods. In Iceland it was boiled in milk for porridge, and baked into bread during hard years. That food use says nothing about putting it on your skin.

What are the side effects of Iceland moss (poultice, wash, bath decoction)?

• Allergic contact dermatitis (an itchy, red skin rash), sometimes with small blisters
• Stinging or burning where it is applied, worse on broken skin
• Redness or dryness after repeated use
• A flare of existing eczema
• Possible sun sensitivity, reported with lichen acids but not well studied
• Infection in a wound if the plant material or cloth is not clean

Good to know:

The main risk is an allergy, and it is a real one.

Lichens are a known cause of contact allergy. Forestry workers and people sensitive to oakmoss in perfume react most often. The reaction can build up after several uses, so a first trouble-free use proves little.

Serious harm from skin use is rare in the record. But the record is thin, and no safety trial has been done.

How much Iceland moss (poultice, wash, bath decoction) should you take?

• Recommended daily: No amount is set for use on skin, because no study has tested one. Packs of dried Iceland moss usually carry a tea amount, not a skin amount. A typical label gives about 1 to 2 teaspoons (roughly 2 to 4 g) of the dried plant per cup of water. Old bath recipes used the same brew made in a larger pot and strained before use. That is what labels say. It is not a direction for your skin. Most sources advise a patch test first. That means a small dab on the inner forearm, left for a day, to check for a rash before wider use.
• Best time of day: The time of day does not matter. For dry skin, many people use a wash or bath in the evening. Skin holds water best right after bathing, so a plain moisturiser straight after a bath is a reasonable habit.
• With or without food: Food does not apply to a poultice, wash or bath. Do not swallow the wash or the bath water. If you also drink Iceland moss as a tea, the plant slime can slow down how your body takes up medicines, so keep the two a few hours apart.
• Time to effect: Any soothing feeling tends to come at once, and it comes from warmth and water as much as from the plant. The slippery film may make skin feel softer for a few hours. That feeling fades as the skin dries. It may do nothing at all for your problem, and nothing about this plant speeds up wound healing in people.
• How long to take it: Short-term use only is the sensible limit, and that is a safety judgement rather than a tested one. Skin that is dry or itchy should start to feel better within days. If nothing has changed after one to two weeks, stop and see a doctor. Repeated contact over weeks raises the chance of an allergy building up to lichen acids.