Oak is used as a natural remedy for mild diarrhea and irritation affecting the skin and mucous membranes
- Characteristics and properties
- How to use it
- Contraindications, side effects and interactions
Characteristics and properties
The Quercus genus includes numerous species of plants belonging to the Fagaceae genus, which are spontaneously spread in Europe and Asia. Symbol of strength and vigor, oaks are long-lived trees, which can reach considerable heights, up to 30-50 meters.
The oak bark is thick, cracked, gray-brown in color and the branches are very leafy, with shiny leathery leaves on the upper side. The flowers are yellowish and pendulous catkins, while the fruits – which ripen in autumn – are oval acorns 2 to 3.5 centimeters long, green when unripe and brown when ripe. Acorns, in addition to being a food that wild boars are greedy for, can be roasted and used to prepare a coffee substitute, as happens with the roots of dandelions and chicory.
Of the oak, herbal medicine and phytotherapy mainly use the bark of different species, in particular Quercus robur, Quercus petraeae and Quercus pubescenses, respectively known by the common names of English oak, oak and downy oak.
The main constituents present in oak are tannins, gallic acid, bitter substances, flavonoids. Oak has antidiarrheal, astringent, antiseptic, anti-inflammatory, analgesic and astringent properties.
The bark, taken from the young branches in spring, is therefore used in mild inflammations of the skin and mucous membranes and in diarrhea due to the presence of tannins with protective properties.
Another species used for medicinal and therapeutic purposes is Quercus infectoria, a plant that grows throughout the eastern Mediterranean area. In phytotherapy, galls are used, rounded formations that form at the level of the buds and young branches following the puncture and the deposition of the eggs of Cynips or Diplolepis gallae tinctoriae. When the gem is attacked by the insect, it undergoes an abnormal growth of a globular shape and hard consistency, called galla. The galls of the oak contain hydrolysable tannins, gallic and ellagin acids, starch and triterpenes. From the galls, collected before the adult insect comes out, a compound known as tannic acid is extracted, used as an astringent and haemostatic for external use.
In Italy some of the species of oak present are, in addition to English oak, oak and downy oak, also the cork oak (Quercus suber), the Turkey oak (Quercus cerris) and the holm oak (Quesrcus ilex), used to obtain wood and cork.
How to use it
Oak is available in herbal medicine in the form of dry drug or dry extract or liquid. The dry oak drug, consisting of the dried and chopped bark of the young branches, is used to prepare a decoction useful for the treatment of numerous ailments. The oak decoction is prepared by boiling the bark 3 grams for 10 minutes in 350 milliliters of water, and then filtering.
For internal use, the oak decoction is useful in case of mild acute diarrhea, taking up to three cups a day for a period not exceeding three days and avoiding exceeding the dosage of 9 grams of bark per day.
Externally, the decoction is prepared with 20 grams of oak bark per liter of water and can be used lukewarm for local applications in case of hemorrhoids, chilblains, breast fissures, anal fissures, small wounds or inflammation of the skin and mucous membranes. In case of inflammation of the mouth and throat, for example, the decoction is used to rinse and gargle, while for irritations of the vaginal mucosa it can be used for external washing.
The decoction obtained from oak bark is also useful in case of dandruff: in this case it is used for rubbing the scalp to be repeated daily, once a day.
Oak bark is also used for baths, foot baths and washes in case of skin irritation, excess sebum and excessive sweating. In this case, 5 grams of bark are added to hot water. The recommended time for baths is 20 minutes.
In herbal medicine there is also the oak bud extract, useful in case of hypotension and fatigue in the amount of 50 drops to be taken once-three times a day in case or, before meals to regularize the intestinal function.
Finally, with the powder obtained from roasted and ground acorns it is possible to prepare an alternative drink to traditional coffee. Acorn coffee is nourishing, restorative and tonic and has a regulating action on the intestine.
Contraindications, side effects and interactions
Oak does not seem to have any particular side effects and contraindications. However, the preparations obtained from this plant must not be taken in case of hypersensitivity or allergies to one or more components.
The use of oak is also not recommended during pregnancy and breastfeeding, as well as before an operation.
In addition, preparations for internal use should not be administered for more than three days.
As for the interactions, the intake of oak can decrease the absorption of drugs containing alkaloids and other basic molecules.
European Mecidines Agency