Iceland moss is the common name of Cetraria islandica, a lichen that grows in the northern and alpine regions of Europe. Lichens consist of a fungus and a photosynthetic organism such as an alga or a cyanobacteria that live together in a symbiotic relationship. Lichens grow on barks, stems and leaves of trees and in soil. Dried Iceland moss is used to make tea, liquid extracts and tinctures that are used medicinally.

Lichens absorb their nutrients from the environment through photosynthesis, because of which they are easily contaminated by environmental pollutants. Most lichens in Europe were contaminated by the fallout from the Chernobyl nuclear plant accident, and Iceland lichens were relatively safer because they received less radioactive contamination.

Iceland moss has been traditionally used as an herbal remedy for many conditions such as cough, bronchitis, sore throat, indigestion and other conditions, however, there are no scientific studies that establish its benefits. Studies indicate bioactive substances in Iceland moss may have antioxidant, antimicrobial, anti-inflammatory, antiemetic and soothing properties. Iceland moss is also believed to promote lactation.

The primary therapeutic benefits of Iceland moss may be from lichenin, a type of lichen starch, and organic acids such as usnic, cetraric, ascorbic and folic acids. Lichenin, when boiled, forms mucilage, a type of gel-like soluble fiber that may be soothing on irritated mucus tissue in the mouth, throat and gastrointestinal tract. The organic acids are bitter and may stimulate digestion and have anti-inflammatory and antimicrobial properties.

In Europe, animals such as reindeer, caribou, musk ox and moose eat Iceland moss as food and people drink it as tea or add it to soup, bread, salads and jellies. Iceland moss has been historically used to make dyes, alcohol, perfumes, toothpastes and skin care products. In the U.S.A., Iceland moss is regulated by the FDA and is allowed only as a flavoring agent in alcoholic beverages. The suggested medicinal uses of Iceland moss include:

• Cough
• Bronchitis
• Sore throat
• Fever
• Indigestion (dyspepsia)
• Loss of appetite
• Vomiting
• Gastroenteritis
• Food poisoning
• Tuberculosis
• Vaginal discharge (external use)
• Healing of wounds and boils (topical application)

Warnings

• Prolonged and excessive use of Iceland moss can cause gastrointestinal irritation and liver problems.
• Rarely, external use may trigger hypersensitivity reactions.

Iceland moss has no reported side effects with recommended doses. High-dose related side effects include:

• Nausea
• Loose stools
• Stomach irritation
• Liver problems

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

• Serious heart symptoms include fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness;
• Severe headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
• Severe nervous system reaction with very stiff muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, and feeling like you might pass out; or
• Serious eye symptoms include blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

There is insufficient information to determine what might be an appropriate dosage of Iceland moss. Suggested dosing:

Dried Plant

• 4-6 g/d orally, divided three times daily

Tea

• 1 cup several times daily. Steep or simmer 1.5-3 grams of the dried plant in 150 mL boiling water for 5-10 minutes and then strain

Overdose

Iceland moss gets contaminated easily, and prolonged and excessive use may be unsafe. Overdose of Iceland moss can cause nausea, loose stools, gastrointestinal irritation and liver problems. Symptoms should resolve on their own with discontinuation of Iceland moss.

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

• Iceland moss has no known severe, serious, moderate, or mild interactions with other drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

• Iceland moss can be easily contaminated and is possibly unsafe to use during pregnancy or nursing. Avoid taking Iceland moss if you are pregnant or breastfeeding.
• Do not use any herbal supplement without first checking with your healthcare provider if you are pregnant or breastfeeding.

• Iceland moss is likely safe for most people if taken in small amounts for short periods.
• If you take Iceland moss, follow the manufacturer's instructions exactly. Natural products are not necessarily safe always and following suggested dosing is important.
• Check with your healthcare provider before taking any herbal product, including Iceland moss, particularly if you have any health conditions or if you are taking any regular medications.
• Herbal products often contain many ingredients. Check labels for the components in any herbal product you purchase.
• Iceland moss is regulated by the FDA and is approved only as a flavoring agent in alcoholic beverages. Iceland moss may be still be found as a component in herbal products that are not regulated by the FDA. Herbal products may differ in formulations and strengths, and labels may not always match contents. Exercise caution in choosing your product.
• Store Iceland moss safely out of reach of children.
• In case of overdose and persistent symptoms, seek medical help or contact Poison Control.