Usnea (Usnea spp.)

Lichens or Lichen family

Plant name: Usnea spp.
Family: Usneaceae
Common names: Old man’s beard

Many different species of Usnea are used as medicine, including U. hirta, U. barbata, U. florida, U. longissima, U. dasypoga, U. bayle and U. lobata. It has a recorded history of therapeutic use dating back to ancient China (where it was called Sun-lo and used for cooling an overheated system and as treatment for surface infections) and it was mentioned in the Formulary of Al-kindi ca. 850 AD.


Usnea is a lichen (part fungus, part algae) which lives throughout the northern temperate zones, especially the sub-arctic and coastal rainforest areas. Usnea has a preference for old growth trees and its habitat is being steadily eroded by modern logging practices. Usnea should only be bought from certified wildcrafters who understand the ecological cycles and will not over harvest. Usnea also has the tendency to accumulate heavy metals from the air so caution is required when harvesting to ensure that there is sufficient distance from any significant sources of pollution.

The plant has a greyish green color and grows as a bushy mat from a few inches to two or three feet long, hanging off the trunks and branches. It feels dry and coarse. Some species have an inner core of white material which may be exposed by gently pulling on either end of a strand. The outer coating will tear apart to reveal the tough inner cord. It is believed to provide tensile strength to the strand and may be a polysaccharide food store. These white-cored species are considered to offer the most valuable medicinal effect. When buying Usnea you should look for this white inner core.

Constituents and actions

Because of their long tradition of use as antimicrobial agents by indigenous peoples, lichens attracted attention early on in the search for antibiotics. By 1944 it was found that as many as half the lichens studied contained lichen acids which exhibited variable antibiotic activity. They are particularly active against gram positivebacteria such as streptococcus, staphylococcus and mycobacteria and are generally not effective against gram negative bacteria such as salmonellaand E. Coli.

Medicinal Use of some species of Usnea

  • Usnea hirta: usnic, thamnolic & usnaric acids, antibiotic
  • Usnea barbata: barbatolic, usnic, lobaric, tartaric acids, used homeopathically against headaches and sunstroke
  • Usnea Florida: usnic, stictinic & lobaric acids, antibiotic and anti-tubercular
  • Usnea longissima: usnic & evernic acids, expectorant

Usnic acid and its derivatives appear to be the main active constituents in Usnea spp. It is believed to work against gram positive bacteria by disrupting cell membrane functions and so preventing ATP formation and oxidative phosphorylation. Human cells are less permeable to usnic acid and so are not adversely affected. Usnic acid is only poorly water-soluble so tinctures with about 70% ethyl alcohol will allow a faster action while simple decoctions are suitable for long term use.

Unidentified constituents in Usnea spp. have also been suggested as offering an immuno-modulating effect upon the whole leucocyte protection system but this has not yet been clincally evaluated. Usnic acid had, in an in vitro experiment, completely inhibited the growth of human tuberculosis bacillus in dilutions as low as 1 : 50,000 and weakened their growth at dilutions of only 1 : 200,000. It also inhibited the growth of streptococcus, Staphylococcus and Pneumococcus at a dilution of 1 : 20,000.

Clinical applications (compiled from discussions with clinical herbalists, based on empirical evidence)

Antifungal – effective against tinea infections such as ringworm, athletes foot and also against Candida albicans.

Antiparasitic – effective against Trichomonas and Chlamydia in vaginal infections.

Antibacterial – effective against gram positive bacteria in local or systemic infections

Immune regulator & supporter – boosts the immune system in cases such as acute and chronic lung infections (pleurisy, TB and pneumonia, colds and flus and any other time of poor immune function.

Dosage and pharmacy

Traditional uses of Usnea include dusting the powdered herb directly onto open or infected wounds, making strong decoctions, and tincturing the herb in alcohol to optimize the immune enhancing effect. It is also successfully employed in a salve where fat is used as the solvent for lichen acids.

Tincture 1 : 3, 70% alcohol standard adult dose is 3 ml three times daily or more in acute cases.


Caution should be used if applying the herb directly to the skin because an allergic contact dermatitis may occur. In this event, try using the herb internally instead. There are no reported side effects of using the tincture or decoction. Many herbalists consider it a safe herb to use in autoimmune conditions, where the immune system is over active and attacks selected tissues of the body, but I would advise caution and regular monitoring of blood components and immune fractions.

Part used: Whole lichen.
Taste/smell: Astringent, bitter.
Tendencies: Drying, cooling.
Dosage: 1:5 dry strength liquid extract: 20-60 drops 1-4 times per day.
Mental picture and specific indications: Usnea is indicated for infectious conditions with fever.

Use: (a) Antibacterial, (b) Antifungal, (c) Antispasmodic, (d) Antipyretic, (e) Analgesic. Used in respiratory, urinary and fungal infections.

Category: Cool herbs that transform hot phlegm

Properties: Bitter sweet neutral

Western Functions: Antibiotic, antiseptic, antifungal.

Energetic Functions:

  • Opens the chest
  • Removes damp heat and transforms phlegm
  • Stops bleeding
  • Invigorates blood
  • Clears heat and toxins
  • Clears deficiency heat

Habitat: Old growth trees in cool areas

Caution: Not in pregnancy. May cause contact dermatitis in topical use, discontinue if rash develops. If used in autoimmune conditions, monitor immune status carefully.

Preparation: Tincture (1:3-5. 50% alcohol) or decoct

Dosage: 10 grams in combination, or powdered in a capsule. Tincture: 3-4 ml 3 times per day. For tuberculosis, tincture, 2-7 droppers 3 times per day for 6 months.


  • Anti bacterial against TB, Pneumococcus, Streptococcus hemolyticus, Corynebacterium diptheriae.
  • Selective for gram positive bacteria.
  • Antidotal against toxins from tetanus and diptheria.
  • Anti protazoan against Trichomonas vaginalis.
  • Carcinostatic in rats.
  • Vasodialator. Also relaxes muscles of the uterus, bronchi, and intestines.


In Native American traditions Usnea represents the north and maintains the “lungs” of planet earth. In those traditions Usnea has a sacred primeval relationship with the trees, helping to protect them against infections. Homeopathic for headache and sunstroke. Usnea is not actually a plant but a lichen, which is part algae and part fungus. Identified as the lichen is pulled apart to reveal a soft threadlike “core”. Usnea is always round. Usnea was historically used as a bitter tonic. Used as medicine in Ancient Egypt, Rome, Greece, and China since before the time of Christ. Outer portion is anti bacterial. Inner portion is has polysaccharides and may be immune boosting.

Kills microbes by disrupting cellular metabolism (preventing ATP formation) rather than destroying the cell structure. It is estimated that 50% of lichens have antibiotic properties. Use of Usnea was documented in “The Formulary of Al-kindi”, A.D. 850 Usnea is becoming rare and should only be picked in genuine need. Only take what you need! Take it from downed branches if possible. Usnea often grows on old-growth trees, it is imperative to not over harvest. Avoid gathering Usnea from heavily polluted areas, as it can absorb heavy metals from the air.

Author: Life Enthusiast Staff