Woad: Applications, Treatments, Health Benefits

Woad, botanically Isatis tinctoria, is a plant of the cruciferous family and is native to western Asia. From the biennial plant, cultivated in Europe as a dye plant, a deep blue dye was obtained, indigo.

Occurrence and cultivation of woad.

In the coloring of medieval clothing, textile dye from the plant, which was considered the king of dyes, played a central role. The name already gives it away. Woad, often called woad for short, was used as a raw material for dyeing fabrics, especially linen. From it comes the blue dye indigo. The history of Isatis tinctoria goes back to antiquity. It is known from Caesar’s records of his campaigns that Celts and Britons painted their faces with a blue-green dye in order to appear as fearsome as possible to their enemies in battle. Corresponding findings in Dragonby, England, in northern North Lincolnshire, indicate that it must have been dyer’s woad. Textile dye from the plant, which was considered the king of dyes, played a central role in the coloring of medieval clothing. It originated in Western Asia, but came to Europe in ancient times. Until the 17th century, woad was cultivated in England, southern France, Alsace and Germany. The cultivation of woad brought wealth to whole regions. For example, the city of Erfurt in Thuringia, where there had been vast areas of cultivation since the 9th century, became so prosperous that it was able to lay the foundation stone for its university. The Thuringians supplied their woad to the then cloth city of Cologne, and via the port cities of Bremen, Lübeck and Hamburg, exports also went to Great Britain and the Netherlands. However, Indian indigo outstripped woad as it provided about 30 times more dye. The herb was completely forgotten with the production of a synthetic indigo at the end of the 19th century. Today Isatis tinctoria is an overgrown plant, but can still be found throughout Europe. It grows on rocks, in vineyards, on slopes, in quarries and in weed corridors. Dyer’s woad is quite undemanding and likes a dry, nutrient-rich, calcareous soil. The plant grows up to six feet tall and is covered with tiny yellow flowers from May to July. From them in autumn develop black-brown pods with the seeds. Vegetative reproduction of the herb occurs through the root shoots.

Effect and application

Even when woad ceased to play a role in the production of the textile dye indigo, the plant retained its importance as a medicinal herb. For 3000 years, traditional Chinese medicine has sworn by its healing properties. The Chinese used the root (Isatis Radix) of the herb against flu-like infections, mumps and measles. Even when the SARS epidemic broke out in China in 2003, woad, which the Chinese call banlangen, was used against the infectious disease, which was caused by a previously unknown coronavirus. However, an evidence-based effect against viruses could not be proven so far. Nevertheless, homeopathy also relies on woad against certain viral diseases. Hahnemann, during his lifetime, also administered the leaves of the plant against worms, jaundice and melancholy. Hahnemann also observed horses suffering from druse, a highly contagious bacterial infection, chewing the herb and showing relief from their symptoms. It is reasonable to assume that this is where the mustard oils exerted their antibacterial effect. Recent studies have shown that the herb contains large amounts of the cancer-preventing glucobrassicin, 20 times more than broccoli. The anti-cancer effect concerns especially breast cancer, because glucobrassicin is able to neutralize toxins in the organism, which include mainly estrogen derivatives. Such results confirmed the naturopaths who knew about the cytostatic effect of woad already in the Middle Ages. Hildegard von Bingen also appreciated woad as a medicinal herb. She boiled a decoction of the plant, mixed it with vulture fat and deer tallow, and used it to make an ointment that she applied to her patients for paralysis.

Importance for health, treatment and prevention.

Today, Isatis tinctoria is gaining importance in other areas as well. Thus, it is often a component of cosmetic products against stressed skin. In wood processing, the use of woad is valued for its fungicidal and insecticidal action.It can be effectively used against long-horned beetle and cellar rot, and is therefore used for biological wood preservatives. The plant is also commonly found as an ingredient in biological paints. The uses in the woad plant in natural medicine are also diverse. The whole plant is used: leaves, flowers and roots. From the roots can be made a bitter liqueur against colds. Psoriasis patients are treated with a tincture of dried leaves with considerable success. Lichens and eczema also respond very well to woad. Oils pressed from the seeds are effective against a variety of skin diseases. The valuable glucosinolates (mustard oil glycosides) make woad a natural antibiotic with antimicrobial properties against bacteria and fungi. It is mainly these oils that are pharmaceutically effective, for example, against stomach ulcers and for gastrointestinal problems. The herb can also be used to reduce fever, stop bleeding in minor wounds, against inflammation and to strengthen the immune system. To gargle against sore throat and cough, a tea is prepared from roots or leaves. It can also be used to treat fungal infections of the mouth and throat. With the fresh leaves of woad have a blood-cleansing effect in spring salads. And in autumn, the seeds provide a delicate edible oil.