Woad as natural antibiotics | Joybilee® Farm | DIY | Herbs | Gardening |

Isatis tinctoria for a broad-spectrum antibiotic

I have a guest post on the Herbal Academy of New England blog about using one of my favorite herbs, Dyer’s Woad, as a natural antiviral. It works so well as an antiviral because it is also a natural antibiotic and so it prevents secondary infections.  Woad and other Isatis spp have been used in Traditional Chinese Medicine for thousands of years for their unique ability to prevent viruses like influenza and measles from replicating in human cells.  Check out my post to find out more about this unique and generous plant.

A brief history of woad

Isatis tinctoria or dyer’s woad is an easy to grow biennial that originated in the Caucus area, near Turkey. It was valued for its rich blue pigment and archeological evidence traces its use as a natural dye back to the Neolithic period in France, the Bronze age in Austria and Germany, the Iron Age in Northern Europe and the British Isles, and the Pharaonic period in Egypt. Woad dyed textiles were found in the pyramids that still showed a blue color after thousands of years.

Even after the invention of modern chemical dyes, woad continued to be used commercially along with natural indigo to dye the military and police uniforms of Europe, until the last woad mill was closed during the Great Depression.   But the story doesn’t end there. Woad continued to be used by gardeners, artists, and hobbyists throughout the 20th century. Today there is a small scale commercial resurgence in the UK and Europe, where woad is being explored as an eco-friendly blue dye, inkjet pigment, and medicinal herb.


Dyer’s Woad can be invasive. It is considered noxious in 8 states and in parts of Canada. It’s on the watch list in BC. If you decide to grow it, please use the first year plants and harvest the root before it flowers. If you plan to save seed, do keep at least 4 plants for seed, to ensure the vitality of the seed, but only allow one flowering stock from each of the plants to remain. Prune off the other branches at the crown, as soon as you see the broccoli-like florets emerge. Harvest the seed when it turns blue-brown, and dry it in a safe area where the wind can’t scatter it recklessly. Better yet, if you are in zone 5 or warmer, grow Isatis indigotica, Chinese Woad, and leave Dyer’s Woad for harvesting from the wild. All Isatis spp. are used interchangeably for herbal medicine

Isatis spp as a broad-spectrum antibiotic

Isatis has a broad range of tested antimicrobial actions against Toxoplasma gondiiPlasmodium falciparumLeishmainia spp., Trichophyton schoenieiniiAspergillus nigerCandida albicansTrichophyton simiiMacrophomina phaseolinaBacillus pasteuriiBacillus subtilisB. spharericusPseudomonas spp., E. coliSamonella spp, Staphylococcus spp. Streptococcus spp. and Clostridium difficile.

How to use Isatis as a natural antibiotic:

Make a decoction of the root

Make a decoction of coarsely ground root using 1 oz. of root to 8 oz of water.  Simmer for 15 minutes with a lid on the pot.  Turn off the pot.  Allow steeping for 15 minutes.  Strain and drink 1 cup 3 times a day.

How to make an Isatis spp tincture

Check out my post on HANES for the special technique I use to make a tincture with Isatis spp leaves and root.


I hope you’ll consider wildcrafting woad leaves, and roots or adding them to your garden,  to appreciate their antiviral and antibiotic virtues as well as to enjoy woad blue — a unique color that can’t be duplicated with chemical dyes.

If you are looking for directions on how to extract the natural indigo dye from woad, see Sarah’s instructions at WearingWoad.com


My own love of woad began 15 years ago when we grew our first woad plants for dye extraction. Making friends with other woadies around the world, including Teresina Roberts of UK, encouraged my daughter to launch an all-consuming science project that took her to the medals podium at the Canada-wide Science Fair 2 years in a row. Together, we’ve explored every aspect of woad from the historical significance, cultivation, natural dyeing, economics, and medicinal use.  Find out Sarah’s unique technique to extract the most dye from Woad’s first-year leaves at WearingWoad.com.


Buhner, Stephen Harrod. Herbal Antivirals, natural remedies for emerging and resistant viral infections. Storey Publishing: North Adams, Ma, 1913. Pp. 192-208.

Cardon, Dominique. Natural Dyes, sources, traditions, technology, and science. Archetype Publications: London, 2007. Pp. 367- 376.

Shu-Jen Chang, Yi-Chih Chang, Kai-Zen Lu, et al. “Antiviral Activity of Isatis indigotica Extract and Its Derived Indirubin against Japanese Encephalitis Virus,” Evidence-Based Complementary and Alternative Medicine, Volume 2012 (2012).

Yang Z, Wang Y, Zheng Z, et als. “Antiviral activity of Isatis indigotica root-derived clemastanin B against human and avian influenza A and B viruses in vitro,” International Journal of Molecular Medicine [2013, 31(4):867-873].

Zifeng Yang, Yutao Wang, Shan Zhong, et al. “In vitro inhibition of influenza virus infection by a crude extract from Isatis indigotica root resulting in the prevention of viral attachment,” Molecular Medicine Reports, March 2012, Volume 5 Issue 3


Isatis spp. as natural antibiotics, have a broad range of tested antimicrobial actions against diverse classes of microbes and viruses.

Source: Woad as natural antibiotics | Joybilee® Farm | DIY | Herbs | Gardening |

Making a Woad Anti-Viral Tincture

Isatis Anti-Viral Tincture

An adaptation of Buhner’s method
Yields 1 quart


2 ounces dried Isatis root, ground
4 ounces dried Isatis leaf, ground
½ ounce piece of licorice root, ground (synergistic)
3 ½ cups water
1 tablespoon apple cider vinegar
1-inch piece of fresh ginger root, peeled and grated (synergistic)
1 cup 100 proof vodka

  • In a 2 quart pot, mix the Isatis leaves and root and the licorice root with water and vinegar. Bring to simmer. Cover the pot and simmer for 30 min.  You’ll want a window open for ventilation when you do this.  It smells strongly of cooked cabbage.
  • Cool it rapidly to room temperature by placing the pot of water in a sink of cold water.  Ensure that the pot doesn’t tip.  If you’ve ever extracted the dye from Isatis leaves you’ll notice how similar the extraction of the medicinal alkaloids is to the extraction of the indigo precursors from the fresh leaves.
  • When the mixture has cooled, pour both the decoction and the plant matter into a 1 quart, wide-mouth mason jar with a lid.  Add the fresh, grated ginger root.  Add the alcohol.  Cap tightly.  Shake once a day.
  • After 2 weeks, strain the liquid.  Squeeze the spent herbs (marc) to extract as much of the liquid as possible.  Compost the marc.
  • Bottle the liquid in colored glass bottles and label.


For prevention: 30 drops up to 6 times per day.

In acute condition: 1 tsp every 2 hours up to 10 tsp per day.

Do not use the full dose for longer than 3 weeks.


Isatis will potentiate the effects of antibiotics and viral vaccines.  Don’t take Isatis at full strength longer than 3 weeks.  Isatis should not be used in cases of kidney disease with renal failure or by those on dialysis. It can induce a deep chill if used for longer than 3 weeks, which resolves after the herb is discontinued.  The leaf tincture can occasionally cause nausea.  No adverse reactions have been reported in scientific studies.  It can be used with caution in children.  Consult your practitioner for guidance.

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