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Botanical name

Common oak or English oak - Quercus robur L.
Holm oak, Sessile oak and Durmast oak - Quercus petraea(Matt.) Liebl.
Downy Oak - Quercus pubescens Willd.


Beech family (Fagaceae)

Useful information about the plant

The oak was already around in the Cretaceous period. It is characterised by its longevity of up to 2000 years, and they can reach a height of 45m and a trunk diameter of several metres. They impress people at all times with their highly individual, even idiosyncratic form and in ancient cultures they were consecrated as powerful deities. It was revered by many Indo-European people as a sacred tree, in Greece it was Zeus, the Romans dedicated it to Jupiter and Thor among the Germans. Celts, Teutons and Slavs made their sacrifices in oak groves. Many oak trees were felled over the course of Christianisation. Shrines with Mary were then brought in connection with the oak tree. They were also regarded as a symbol of strength and as a symbol of heroism in the 18th century in Germany.
The main area of the genus Quercus is located in North America, some species grow in Europe and Western Asia. The Common oak or English oak, the Holm oak, Sessile oak or Durmast oak and the Downy Oak are native to us. The three species resemble each other very much and cross readily. Oaks love the warmth and prefer low, damp areas. They are part of our hardwood forests, on barren ground, the oak is easily driven away by the beech.
Oak is easy to identify with its typical, sinuously lobed leaves and very thick trunk bark. Its fruits are acorns, nuts, individually set in a scaly fruit cup, the cupula. The foliage of the trees is rather light. The English oak (Q. robur), most common in Europe, usually has a short trunk and a more spreading crown. It also grows as a solitary tree. Its English name refers to the long-stalked fruits, the epithet robur alludes to the darker colour of the sapwood of the hard core wood (from Latin "ruber" = red). It flowers earlier than the Sessile oak and is therefore called "Summer Oak", the Durmast oak (Q. petraea) is the "Winter Oak". It has a higher trunk, fruit and likes to grow on dry stone ground, which is reflected in its name epithet petraea (Greek "petraios" = rock). The Downy oak (Q. pubescens) grows mainly in southern Europe, in Germany it is only found in the warm southern slopes of the Rhine Graben. It is significantly smaller (20m) and its young twigs and leaves have delicate hairs, which is reflected in its name, epithet pubescens (Latin "pubescens" = down fluff). The oak is a crop, because it is processed into high-grade lumber. Previously, the bark was used because of its tannin content for the tanning of hides. It is also used as an evergreen, Western Mediterranean cork oak (Quercus suber) with its up to 10cm thick bark, which is processed into cork.

Medicinally used plant parts (drug)

The dried bark of fresh, young branches of the three oak species is used. The commercial drug comes from various Eastern and Southern European countries.

Ingredients of the drug

The oak bark contains tannins, predominantly condensed tannins (catechin tannins).

Descriptions of the quality

The quality of the oak bark (Quercus cortex) is specified in the European Pharmacopoeia (Ph. Eur).

Medical Application

Recognised medical use

Externally for inflammatory skin diseases; internally for unspecific, acute diarrhoeal diseases, in addition to the external treatment of mild inflammation in the mouth and throat and in the genital and anal area (Commission E).
The HMPC has classified oak bark as a traditional herbal medicinal product (see "traditional use").

Traditional use

The HMPC classified oak bark as a traditional herbal medicine (§ 39a AMG). Based on many years of experience, oak bark has been taken internally for the symptomatic treatment of mild diarrhoea, and externally applied for mild inflammations of the skin and mucous membranes. Oak bark is also used to relieve itching and burning of haemorrhoids, if a serious disease has been medically excluded.

Medicinal herbal preparations in finished drug products

  • chopped oak bark as a tea
  • alcoholic extracts in a bath


Prepared drugs: see package insert;
Tea infusion: For diarrhoea drink a cup of oak bark tea 3 times a day. 3g daily dose of the drug. For external use only (flushing, compresses, gargle solution, baths) applied several times a day.

Preparation of a tea infusion

For internal use: mix 1g of finely chopped or coarsely powdered drug with cold water, boil and strain after 5 min. For external use only (flushing, compresses, gargle solution), prepare 20g of the drug with 1 litre of water, for full and partial baths prepare 5g of the drug in 1 litre of water in the same way.


For more persistent and recurrent diarrhoea and blood in the stools, it is essential that you seek medical advice. With febrile and infectious diseases, cardiac insufficiency (heart failure), and high blood pressure, the bath should not be taken hot. Oak bark decoctions may not be used with weeping, extensive eczema and skin injuries.
There are still no studies on the harmlessness of the use of oak bark during pregnancy and breast-feeding, and for use in children and adolescents under the age of 18.

Side effects

Allergic reactions at most.


Not known for external use; when the oak bark is taken internally, it may delay the absorption of concomitantly administered drugs, oak bark should therefore be taken at least 1 hour (before or after) the other drugs.


Drug monographs

HMPC, Commission E

Further reading

Wichtl: Teedrogen und Phytopharmaka, pg. 543
Schilcher: Leitfaden Phytotherapie, pg. 85
Van Wyk: Handbuch der Arzneipflanzen, pg. 265
Kommentar zum Europäischen Arzneibuch (Oak bark, no. 1887)

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