A lichen — a symbiosis of fungus and algae — that grows on trees worldwide and has been used across many traditions as a potent antimicrobial. Contains usnic acid, one of the most active natural antibiotics known, effective against gram-positive bacteria including streptococcus and staphylococcus. Widely used in Western herbal medicine for throat infections, respiratory illness, and topical wound care.
whole lichen (thallus)
tincture, decoction, topical wash, lozenge
2–4ml tincture 3–4× daily; decoction 2–3 cups daily during infection
Generally safe at recommended doses. High-dose usnic acid has shown liver toxicity in supplements — use as prepared herb, not isolated extract. Avoid in pregnancy.
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