The summer oak (lat. Quercus robur ) is a tree that reaches 30 m in height with a branched crown and thick stems. The bark of the stems and large branches is thick, with many cracks, brown-gray, and on young branches it is thin and smooth. Summer oak blooms in early spring. It is widespread in our country mainly in the lowlands and along the rivers. It is less common than the common oak, which is widespread in the foothills and mountain belt up to about 1500 m above sea level.
Summer oak has astringent, hemostatic and anti-inflammatory effects. The content of gallotannins and catechin tannins determines the wide application of barks from young oak branches. They are mainly used for external use in a large number of skin diseases , especially in purulent wounds and pimples, eczema , cracked skin, itching, etc. They are also used for white discharge in women, for hemorrhoids, for inflammation of the gums and tonsils, for bad breath, etc. Very rarely and in small doses (since large doses induce vomiting), extracts from the bark of the oak are used internally for inflammations of the stomach and intestines, of the urinary bladder, and for profuse menstruation.
Method of use. For external use, prepare a decoction of 500 g of crushed bark with 3-4 liters of water, which is boiled for 30 minutes. The decoction is added to the bath water. Baths are made with it for skin irritations.
Chemical composition. The dried peels contain an average of 7 - 12% gallotannins and catechin tannins, free gallic and ellagic acid, the flavonoid quercetin, quercitrin, carbohydrates, resins, etc. Young and uncracked bark has been shown to contain a greater amount of tannins than old, cracked and thick bark. The fruits (acorns) contain 4-7% tannins, up to 40% starch, about 4% proteins, 3% fats, 1.5% mineral salts, sugars, etc.
Drugs. For medicinal purposes, the bark ( Cortex Quercus ) and the fruit ( Fructus Quercus ) are used for medicinal purposes, the bark being collected in early spring - during the period of intense sap flow, and the acorns - in autumn, after ripening, when they begin to fall by themselves from the trees. It is not allowed to mix oak bark with ash bark ( Fraxinus excelsior L. ). The outer surface of the ash bark is dull, gray.