Usnea

Parts used and where grown

Usnea, also known as old man’s beard, is not a plant but a lichen—a symbiotic relationship between an algae and a fungus. The entire lichen is used medicinally. Usnea looks like long, fuzzy strings hanging from trees in the forests of North America and Europe, where it grows.

Usnea has been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating	Health Concerns
	Common cold/sore throat Cough Infection Pap smear (abnormal)
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Rating

Health Concerns

Common cold/sore throat

Cough

Infection

Pap smear (abnormal)

Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars

Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star

For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies)

Due to its bitter taste, usnea stimulates digestion and was historically used by herbalists to treat indigestion. It was also reportedly used over 3,000 years ago in ancient Egypt, Greece, and China to treat unspecified infections.¹

Active constituents

Usnic acid gives usnea its bitter taste and also acts as an antibiotic in test tube studies.² Test tube studies have suggested an anti-cancer activity for usnic acid. However, this action has not been sufficient to warrant further investigation in humans.³ Usnea also contains mucilage, which may be helpful in easing irritating coughs. Again, this has not been studied in humans.

How much is usually taken?

Usnea, 100 mg three times per day, can be taken in capsules.⁴ Tincture, 3–4 ml three times per day, can also be used.

Are there any side effects or interactions?

There are no known side effects of usnea. It is considered safe for use in children. The safety of usnea during pregnancy and breast-feeding has not been established.

At the time of writing, there were no well-known drug interactions with usnea.

References

1. Tilford GL. Edible and Medicinal Plants of the West. Missoula, MT: Mountain Press Publishing Company, 1997, 148–9.

2. Weiss RF. Herbal Medicine. Beaconsfield, UK: Beaconsfield Publishers Ltd., 1988, 49.

3. Evans WC. Trease and Evans’ Pharmacognosy, 13th ed. London: Baillière Tindall, 1989, 643.

4. Gruenwald J, Brendler T, Jaenicke C, et al. (eds). PDR for Herbal Medicines. Montvale, NJ: Medical Economics, 1998, 1199–200.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires March 2005.