Slow-growing, long-lived deciduous tree reaching 150 ft (45 m). Has deeply lobed leaves, long catkins, and green to brown fruit (acorns).
Habitat & Cultivation
English oak grows throughout the northern hemisphere, in woods and forests, and along roadsides. The bark is collected in spring and the fruit is harvested in autumn.
Bark, galls (growths produced by insects or fungi).
English oak bark contains 15–20% tannins (including phlobatannin, ellagitannins, and gallic acid). Oak galls contain about 50% tannins.
History & Folklore
Sacred to the Druids, the oak tree has been esteemed in European herbal medicine for its astringent bark, leaves, and acorns.
Medicinal Actions & Uses
English oak bark, prepared as a decoction, is often used as a gargle to treat sore throats and tonsillitis. It may also be applied as a wash, lotion, or ointment to treat conditions such as hemorrhoids, anal fissures, small burns, or other skin problems. Less commonly, a decoction of the bark is taken in small doses to treat diarrhea, dysentery, and rectal bleeding. Powdered oak bark may be sniffed to treat nasal polyps, or sprinkled on eczema to dry the affected area.
Do not take oak bark internally for more than 4 weeks at a time.