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Usnea (song luo)

What is usnea? What is it used for?

Usnea is not an herb, but a lichen – a plant consisting of a fungus combined with a blue-green algae. It is found in the forests of Europe and North America, where it grows in long, fuzzy strings that hang from tree branches.  The lichen’s fuzzy appearance has helped give usnea the nickname of “old man’s beard.”

Usnea’s main ingredient is usnic acid, which gives the plant an incredibly bitter taste.  Because of its taste, usnea has been historically used to treat indigestion.  Usnea also contains mucilage, which can be helpful in easing coughs.  Preliminary test-tube studies have suggested usnic acid may fight certain types of cancer.

How much usnea should I take?

In capsule form, many herbalists recommend taking 100mg of usnea TID. Other practitioners suggest 3-4ml of an usnea tincture TID.

What forms of usnea are available?

Usnea capsules and tinctures are readily available at many health food stores. Whole dried usnea can be found at several specialty food stores.

What can happen if I take too much usnea? Are there any interactions I should be aware of? What precautions should I take?

To date, there are no known side effects from taking usnea. It is considered safe for children. In addition, there is no current evidence of adverse drug reactions with usnea. As always, make sure to consult with a qualified health care provider before taking usnea or any other herbal medicine or dietary supplement.


  • Evans WC. Trease and Evans’ Pharmacognosy, 13th ed. London: Baillière Tindall, 1989, 643.
  • Gruenwald J, Brendler T, Jaenicke C, et al. (eds). PDR for Herbal Medicines. Montvale, NJ: Medical Economics, 1998, 1199–200.
  • Okuyama E, Umeyama K, Yamazaki M, Kinoshita Y, Yamamoto Y. Usnic acid and diffractaic acid as analgesic and antipyretic components of Usnea diffracta. Planta Med April 1995;61(2):113-5.
  • Tilford GL. Edible and Medicinal Plants of the West. Missoula, MT: Mountain Press Publishing Company, 1997, 148–9.
  • Weiss RF. Herbal Medicine. Beaconsfield, UK: Beaconsfield Publishers Ltd., 1988, 49.
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