Iceland Moss Drug Interactions, Uses, Safety & More

Iceland moss is not actually a moss but a lichen — a combination of a fungus and an alga that grow together. It is found in cold, northern regions such as Iceland, Scandinavia, and mountainous parts of Europe and North America.

People have used Iceland moss for centuries as a traditional remedy. The dried lichen is most often made into a tea, used in throat lozenges, or taken as a liquid extract. Its main appeal comes from the slimy, gel-like fibers (called mucilage) it contains, which can coat and soothe irritated tissues.

Iceland moss is most commonly used for a dry, irritating cough and for soothing a sore or irritated throat and mouth. It is also used traditionally for digestive complaints, poor appetite, and general irritation of the mucous membranes.

The scientific evidence is limited. Much of what is known comes from traditional use, laboratory studies, and small or older trials rather than large, high-quality human studies. Some health authorities in Europe accept Iceland moss lozenges as a traditional remedy to soothe throat and cough irritation, based mainly on long-standing use rather than strong clinical proof.

For most other uses — including digestion, appetite, and antimicrobial effects — the evidence in people is insufficient. It should not be relied on to treat infections or any serious medical condition.

The main active ingredients are thought to be mucilage (water-soluble fibers such as lichenan) and bitter compounds called lichen acids (for example, cetraric and fumarprotocetraric acid).

The mucilage is believed to form a soothing, protective layer over irritated tissues in the throat and mouth, which may ease the urge to cough. The bitter compounds may gently stimulate saliva and digestive juices, which is the basis for its traditional use for appetite. Some lichen acids have shown antimicrobial activity in laboratory tests, but these lab findings do not prove the same effects happen in the body.

For most healthy adults, short-term use of Iceland moss appears to be well tolerated. However, product quality varies, and good safety data are limited.

One concern is that lichens can absorb pollutants and heavy metals (such as lead or cadmium) from the environment, so it is best to choose products from reputable manufacturers that test for contaminants. People with allergies to lichens should avoid it.

Pregnancy and breastfeeding: Because there is not enough safety information, Iceland moss is best avoided during pregnancy and while breastfeeding. If you are managing an ongoing health condition or taking medications, talk with your pharmacist or doctor before using it.

Iceland moss is usually well tolerated when used short-term in normal amounts. Possible side effects include mild stomach upset, nausea, or irritation, especially with strong or concentrated preparations.

Allergic reactions are possible but uncommon. Stop using it and seek medical care if you notice a rash, itching, swelling, or trouble breathing. Long-term or high-dose use has not been well studied, so it is not recommended.

There is no official, standardized dose of Iceland moss. Traditional preparations include a tea made from the dried lichen, lozenges, and liquid extracts, and the right amount depends on the specific product.

The safest approach is to follow the directions on the product label and not exceed the recommended amount. Because strengths differ widely between brands, check with your pharmacist or doctor before starting, especially if you have a health condition or take other medicines.