Icelandic Moss

Icelandic Moss

Scientific Names of Icelandic Moss:  

Cetraria islandica (L.) Ach s.l. [Fam. Parmeliaceae]


Dried thallus of Cetraria islandica lichen.

Traditional Usage:  

– Acute Breathing Disorders
– Appetite Loss
– Bronchitis
– Cellular Regeneration
– Cleansing
– Detoxification
– Dry Cough
– Expectorant
– Gastroenteritis
– HIV Infection
– Mouth and Throat Irritation and Inflammation
– Poultice
– Respiratory Problems
– Restorative
– Ulcers
– Urinary System Problems
– Vascular Disorders
– Wounds


Icelandic moss, Cetraria islandica L. [Fam. Parmeliaceae], has traditionally been used as a food and medicine in both Europe and North America. The polysaccharides in the lichen (plant-fungus partnership) form a moist and soothing layer over the mucous membranes of the mouth, throat, and chest making it an effective treatment for mouth and throat infections as well as colds, coughs, bronchitis, and acute breathing disorders. Icelandic Moss has been used to treat inflammation and dryness of the pharyngeal mucosa in naturopathy for many years. The necessary concentration of Icelandic Moss and its therapeutic effectiveness were analyzed in a randomized-controlled clinical study with sixty-one patients who recently underwent nasal surgery. The patients suffered especially from dryness and inflammation due to breathing only through the mouth while the nose was permanently closed by a nasal package. Coating, dryness, and inflammation of the mucosa, lymph nodes, tongue, the tolerance of the drug, and symptoms like hoarseness and sore throat were documented. Icelandic moss lozenges were given from the first to the fifth day after the operation. Treatment with Icelandic moss directly reduced all pathological symptoms. A dose of 0.48 g per day was sufficient. It can be recommended after nasal surgery, after intubation and for simple infections of the throat. It is also used for kidney and bladder problems, pulmonary conditions, as a restorative, and as a topical for infected wounds. Recent studies found compounds in Icelandic moss that are potential treatments for ulcers, abnormal growths and AIDS. University of Illinois scientists discovered compounds from Iceland moss that inhibit an enzyme essential to HIV replication. Conventional drugs including AZT do the same thing, however these drugs are toxic and do not completely inhibit the virus. Conversely, the active constituents in Icelandic moss have been shown in laboratory studies to be nontoxic to cells.

Active Ingredients:  

Icelandic moss contains: 50% water-soluble polysaccharides, including lichenin, a linear cellulose-like polymer of b-D-glucose, and isolichenin, a linear starch-like polymer of a-D-glucose (Wichtl and Bisset, 1994). Also contains galactomannans and an acidic, branched polysaccharide containing D-glucose and D-glucuronic acid units. Other constituents include bitter-tasting lichen acids, including the depsidones fumarprotocetraric acid and protocetraric acid, and the aliphatic lactone protolichesterinic acid.

Suggested Amount:    

Fresh Icelandic moss: Rinse 1.5-2.5 grams of finely chopped Icelandic moss with boiling water, discard then add more hot water. Steep 10 minutes then strain (removes antibiotically active constituents and bitter taste).
Cut Herb: 4-6 g per day
Infusion: 4-6 g of herb in 150 ml of water
Extract: 1:1 (g/ml); 4-6 ml
Tincture 1:5 (g/ml): 20-30 ml.
Do not exceed 8 g per day.

Drug Interactions:  

None known.


Do not use if you have gastro-duodenal ulcers.

Side Effects: 

Icelandic moss has a long history of use as both a food and medicine in Europe and North America and is considered a safe food-type herb listed in most edible wild plant books, including the Peterson’s Field Guides. However, fresh or improperly prepared Icelandic moss contains bitter and potentially toxic lichen acids and it also concentrates heavy metals like lead. Two studies published in 1986 examined the potential toxicity of Icelandic moss and other natural plants used as emergency foods in Finland and northern Europe and found that rats tolerated a 25% (w/w) diet of ash-treated Icelandic moss in 3-month tests rather well, although the body weight did not increase as much as in controls (ash-treatment is a traditional mode of preparation of Icelandic moss as a food). At the end of the experiments, the rats in the lichen group had proteinuria and on autopsy some kidney tubular changes were found probably due to high concentrations of lead in the kidneys due to the lichen consumption (lead deposition in lichens is likely decreasing with the advent of unleaded gasoline). A second study examined several modes of preparation of Icelandic moss and reindeer lichen moss, including boiling, ash-soaking or both. Untreated and only shortly boiled lichens were lethally toxic to mice in 50 and 25% w/w mixtures in food, but when ash-soaking was added mice tolerated Icelandic moss lichen (but not reindeer lichen) reasonably well for 3 weeks. The researchers concluded that unqualified simplification of the traditional precautions for their treatment might be dangerous.


Airaksinen MM, Peura P, Ala-Fossi-Salokangas L, Antere S, Lukkarinen J, Saikkonen M, Stenback F. 1986. Toxicity of plant material used as emergency food during famines in Finland. J Ethnopharmacol 1986 Dec; 18(3): 273-96; Airaksinen MM, Peura P, Antere S. 1986. Toxicity of Iceland lichen and reindeer lichen. Arch Toxicol Suppl; 9: 406-9.

Blumenthal M, Goldberg A, Brinckmann J 2000. Herbal Medicine: Expanded Commission E Monographs. Copyright American Botanical Council. Publ. by Integrative Medicine Communications, 1029 Chestnut Street, Newton, MA 02464. Pp. 212 – 214

Duke, J. 1997: The Green Pharmacy, The Ultimate Compendium of Natural Remedies from the World’s Foremost Authority on Healing and Herbs. Pp. 330. Rodale Press.

Kempe C, Gruning H, Stasche N, Hormann K. 1997. [Icelandic moss lozenges in the prevention or treatment of oral mucosa irritation and dried out throat mucosa] Laryngorhinootologie. 1997 Mar; 76(3): 186-8. German.

Wichtl M (ed). 1994. Uvae ursi folium – Uva ursi leaf. In Herbal Drugs and Phyto-pharmaceuticals. (English translation by Norman Grainger Bisset). CRC Press, Stuttgart, pp. 137-139