What are tannins or tannins?

Tanning agents are also called tannins. There are various ways to classify tannins. Tannins generally have an astringent or astringent effect that causes proteins to precipitate. This effect ensures the healing power of tannins in various ways. The word tannin comes from tanna, a High German word used for both the oak and the pine tree, called Tannenbaum in German. Our word pine tree is a corruption of the old High German word. Oak contains a lot of tannin. You can sometimes notice the astringent effect when you eat a plant with tannins; the mouth will then get the feeling of contracting. NB! This article is written from the personal view of the author and may contain information that is not scientifically substantiated and/or in line with the general view.


  • Classification of tannins
  • Gallotannins
  • Ellagitannins
  • Complex tannins
  • Condensed tannins or oligiomeric and polymeric proanthocyanides
  • Astringent effect
  • Mild disinfectant effect
  • Drying effect
  • Haemostatic effect
  • Mild anti-inflammatory effect
  • Wound healing effect


Classification of tannins

Nowadays, the most common distinction is made in the classification of tannins

  • Gallotannins
  • Ellagitannins
  • Complex tannins
  • Oligomeric and polymeric proanthocyanides



The category of gallotannins includes all tanning agents based on gallic acid. Gallic acid is most common in compounds with glycosides. Gallotannins split when water is added; that process is called hydrolysis. Gallotannins are often found in medicinal plants that cannot be eaten directly, but are used in dilutions as a medicinal plant. Examples include American witch hazel, bearberry, pedunculate oak and Chinese rhubarb.


Ellagitannins are tannins that contain at least two gallic acid molecules. They form the largest category of tannins in nature. Unlike gallotannins, this type of tannins cannot be hydrolyzed. Generic plants in which the substances occur are: silverweed, tormentil and lady’s mantle. It also occurs in American witch hazel; this contains both gallotannins and ellagitannins.

Complex tannins

Complex tannins are also called flavono-ellagitannins. This form of tannins is bound to a flavonoid. An example of this is the Mongolian oak or Quercus mongolica .

Condensed tannins or oligiomeric and polymeric proanthocyanides

The fourth category of tannins have a flavan-3-ol as a catechin. As a monomeric molecule, this tanning agent has no astringent or astringent effect, unlike all other tanning agents. They can also exist as polymers; then they are long chain molecules that do have astringent properties. A polymerization of 2 to 8 catechins is called Oligomeric Procyanides (OPCs). More than eight units are referred to as polymeric proanthocyanides. Condensed tannins are found in: green tea, blueberry, grape seeds, ratanhia and maritime pine or pinus maritimus .

Astringent effect

Tannins have different effects. They precipitate proteins. When there is an inflamed mucous membrane, tannins draw a membrane over that mucous membrane, protecting it. Less mucus can then be released. This is called the astringent effect. This finds medicinal use in the treatment of diarrhea, gastric inflammation and intestinal inflammation. Dried bilberry and tormentil root are the best remedies for diarrhea in herbal therapy. Meadowsweet is a remedy that is used for inflammation of the stomach lining, also called gastritis.

Mild disinfectant effect

Proteins from pathogenic micro-organisms can also be precipitated. In this way, tannins have an antiseptic effect. Gargles are used to neutralize germs in the mouth. The oral mucosa, gums, larynx and throat can be treated with a gargle with common agrimony, silverweed or ratanhia.

Drying effect

Inflamed tissues exhibit excessive secretion. This is slowed down by tannins. It is called the drying or anticattharal action of tannins. Healthy tissue is left untouched by tannins. Different plants are used for different inflamed mucous membranes:

  • Stiff eyebright: on eyes and nose,
  • American witch hazel: on eyes,
  • Spiral female mantle: on vagina.


Haemostatic effect

Superficial, dilated capillaries are also contracted. This stops bleeding and reduces redness of the skin. Medicinal plants that have this function are:

  • Tormentil: for bloody diarrhea,
  • Spiral female mantle: in case of excessive blood loss during menstruation,
  • American witch hazel: for hemorrhoids.


Mild anti-inflammatory effect

Since redness is reduced, mucous membrane secretion decreases and bleeding is stopped, tannins can be called anti-inflammatory. The anti-inflammatory effect always goes hand in hand with the other medicinal effects of tannins. All examples of medicinal plants with tannins mentioned also have an anti-inflammatory effect. Specific examples of other tannin-containing plants include:

  • Bearberry for cystitis,
  • Pedunculate oak for all kinds of skin infections.


Wound healing effect

Applying the protective layer of tannins ensures that damaged tissue is repaired faster. Moisture loss from wounds is limited, allowing the body to repair the skin more quickly. In medical terms it is said that granulation is promoted; granulation is part of the process of producing new skin cells. Medicinal plants that are good for skin repair:

  • Common agrimony,
  • Common yarrow,
  • Robert’s herb.


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