Oak Moss

Reviewed on 6/11/2021
Other Name(s):

Ebernia Prunasti, Évernia, Evernia prunastri, Évernie, Lichen Oak Moss, Mousse de Chêne, Musgo de Roble, Oakmoss, Tree Moss.


Oak moss is the moss from a certain type of oak tree called Evernia prunastri. The moss is used to make medicine.

People take oak moss for intestinal problems.

In manufacturing, oak moss is used as a fragrance in perfumes.

Oak moss is sometimes called tree moss, but so are other products. Avoid confusion by looking for the scientific name, Evernia prunastri.

How does it work?

There isn't enough information to know how oak moss might work as a medicine.


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Uses & Effectiveness

Insufficient Evidence to Rate Effectiveness for...

  • Intestinal problems.
  • Other conditions.
More evidence is needed to rate the effectiveness of oak moss for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

Side Effects

Oak moss might be safe for most people when taken for short periods of time as a water-based tea. When taken in large amounts, for long periods of time, or as an alcohol extract, oak moss is UNSAFE. Oak moss contains a toxic chemical called thujone. It can cause side effects such as restlessness, vomiting, dizziness, tremors, kidney damage, and convulsions.


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Special Precautions & Warnings

Pregnancy and breast-feeding: It's UNSAFE to take oak moss if you are pregnant. It contains a chemical called thujone that might cause the uterus to contract, and this could cause a miscarriage.

Allergy to lichens and mosses: If you are allergic to lichens and mosses, you might also be allergic to oak moss. It's best to avoid oak moss if you have one of these allergies.

A blood disorder called porphyria: Oak moss might make this condition worse. Don't use oak moss if you have porphyria.

Kidney problems: Oak moss might make this condition worse. Don't use oak moss if you have kidney problems.


The appropriate dose of oak moss depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for oak moss. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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Dahlquist I, Fregert S. Contact allergy to atranorin in lichens and perfumes. Contact Dermatitis 1980;6:111-9. View abstract.

Goncalo S, Cabral F, Goncalo M. Contact sensitivity to oak moss. Contact Dermatitis 1988;19:355-7. View abstract.

Goncalo S. Contact sensitivity to lichens and compositae in Frullania dermatitis. Contact Dermatitis 1987;16:84-6. View abstract.

Thune P, Solberg Y, McFadden N, et al. Perfume allergy due to oak moss and other lichens. Contact Dermatitis 1982;8:396-400. View abstract.