Iris has been used for thousands of years as medicine. Modern herbalists most commonly use iris for conditions of the lymphatic and integumentary systems as it possesses a number of effects in supporting the elimination of toxins and metabolic waste products from the body. 

Used in high doses, iris can have an emetic effect (causes nausea and vomiting). In smaller doses, however, iris is considered useful for treating nausea. Due to iris’ narrow therapeutic window (range of dosage between effective and toxic), its use is best under the guidance of a medical herbalist  (1).

Iris has mildly laxative effects due to its potent bitter compounds that stimulate the flow of bile from the liver and gallbladder. This, combined with its ability to increase lymphatic detoxification makes it an excellent herb to include in a treatment approach to inflammatory skin conditions that are caused by congestion or toxicity in the body (2,3).

Iris is especially active on the liver. It is used to treat poor digestion and constipation caused by low bile and liver dysfunction (1).

Culpepper considers iris as hot and dry in the second degree (4). It is energetically pungent, bitter and warming and is most appropriate to use where there is stagnation and atrophy in the mucosa, or where there is a depressed or underfunctioning tissue state in the digestive system, particularly where the liver, pancreas and lower bowel is concerned. Iris increases  secretions in these systems (3).

Iris has a regulatory effect on the mucous membranes and can also be used in cases of dampness in the body — this is most specifically in relation to the lymphatic system. Iris can also regulate discharges and strengthen the mucous membranes  of the stomach. Encouraging flow of bodily fluids, including saliva, lymph, bile, and digestive secretions, iris benefits these organ systems by regulating fluid flow and acting as a tonic restorative(5).

Iris is considered an alterative medicine. Alteratives are traditionally seen as detoxifiers that help to encourage healthy function of the eliminatory systems through the blood and lymph. Through improved elimination of toxins and metabolic waste, alteratives like iris are indicated for a wide range of skin conditions such as eczema and psoriasis (3,6). Joint diseases and other inflammatory conditions associated with toxicity and poor elimination would also be improved by increased clearance, so too would benefit from iris’ virtues (6). 

Andrew Stableford writes in his book The handbook of energetic and constitutional herbal medicine that iris promotes personal expression and creativity (7). It also has a mildly nervine effect, which works directly on rising heat issues. This action indicates the application of iris for treating headaches and migraines (7,8).

As a herb to address the more emotional presentations, iris is indicated where artistic expression and creativity are blocked within an individual. It may also be used for mood changes where excitement alternates with depression and apathy. Iris works on the autonomic nervous system and is thought to support an underfunctioning parasympathetic nervous system. Particularly where there is a pattern of hyperactivity followed by exhaustion, iris too can decrease excessive functioning of the sympathetic nervous system (3).

Iris was used and written about extensively by the early American eclectic physicians. The eclectics were a group of medical doctors practising in the late 1800s and early 1990s.

Finley Ellingwood, an American doctor of eclectic medicine documented its uses in relation to conditions of the liver where symptoms such jaundice, light coloured stools (bilous) and low urine flow were presenting. It was said that all causes of chronic jaundice could be treated with iris.

It was also recommended in cases of irritable and inflamed mucous membranes in the digestive system. Some of the traditional uses of iris for digestive conditions included nausea or vomiting with stomach pain, gastric pain after a fatty meal, diarrhoea with a burning sensation and lower abdominal pain (9).

Iris was indicated to detoxify and decongest atonic tissues. Dropsy (oedema from congestive heart failure) is a condition with atonic tissues, where iris would be indicated to encourage movement in the lymphatic system. Ellingwood also referred to iris as a potent antisyphilitic medicine where the lymph glands were inactive. By its effects on the lymphatic system, it was also indicated in the treatment of skin conditions such as psoriasis, eczema, purulent and open ulcers and to help with a goitre from hyperthyroidism (9).

Iris has long been considered as a blood purifier, this effect is understood as being in relation to its stimulating effect on lymphatic drainage rather than being directly related to the quality of the blood itself. Felter writes that iris is most appropriate for soft glandular enlargements whereas harder enlargements respond better to poke root (Phytolacca americana) (10).

The King’s American Dispensatory mainly refers to its use for the digestive, lymphatic and nervous conditions. Iris stimulates the liver via the biliary duct and improves enzymatic activity via pancreatic and salivary secretions (11).

Digestive system

Iris can be used for conditions of the digestive system largely due to its positive effects on the liver. Its bitter qualities stimulate the liver and gallbladder, which encourage the liver’s metabolic and detoxifying activities. These effects are far reaching across multiple body systems, as the liver is involved in many important processes that affect how the entire body functions. The liver detoxifies the blood via portal circulation, which reduces toxins and metabolic waste products from systemic circulation (5,12). Iris is also sometimes used by herbalists for chronic hepatitis and other hepatic (liver) conditions (13).

In small doses iris can be useful for nausea, in larger doses it was used traditionally as an emetic (to induce vomiting). It is mildly laxative which makes it useful for constipation — particularly where it is caused by poor liver and gallbladder function (12). One of its active constituents called iridin is thought to induce laxative action by causing irritation  to the mucous membranes (1).

Iris stimulates bile production and, therefore, helps to enable many digestive functions including that in the lower bowel (12).

Other indications for iris in the digestive system include duodenal catarrh with jaundice and light coloured stools; cholera infantum and morbus; diarrhoea and dysentery (in very small frequent doses). It works for both diarrhoea and constipation by restoring loss of tonicity to involuntary muscle structures in the gastrointestinal tract and through encouraging the flow of bile from the gallbladder (8).

Iris is also said to have a stimulating effect on the pancreas and helps to improve the functionality of this important organ. It acts by stimulating the biliary, pancreatic and salivary secretions (1,8).

Lymphatic system

Iris is considered a useful herb for the lymphatic system. By supporting the movement of lymph, irisassists in immunological and detoxification processes. It is an effective herb for use where there are congested and atonic tissues throughout the body (9). In Ayurvedic medicine iris is sometimes used to assist with weight loss due to the combined action of its lymphatic and hepatic effects (12).

Preist and Priest state in their book Herbal Medication: A Clinical and Dispensary Handbook that iris is a “positive alterative for chronic torpid conditions. It influences the glandular system, lymphatics, liver, gallbladder and intestinal glands. It is specific for hepatic congestion due to venous or lymphatic stasis” (13). The British Herbal Pharmacopoeia recommends a combination of iris and poke root in the treatment of lymphadenitis (14). 

Iris has a specific affinity to congestion in the throat and head as well as for congestion and carcinoma of the breasts (7). The latter and any such serious condition should only be addressed under the care of a qualified herbalist as part of an integrated approach to oncology.

Iris is traditionally used for a wide range of conditions characterised by swelling that are indirectly connected to the lymphatic system. This includes ascites (fluid build up in the abdomen), anasarca (generalised swelling) hydrothorax (collection of fluid in the pleural cavity that contains the lungs), hydropericardium (fluid in the membrane that surrounds the heart) and dropsy (8).

Endocrine system

Iris is often referenced as having some application for symptoms related to thyroid disorders such as goitre. It acts mainly by reducing swelling and congestion of the enlarged thyroid (7,8). Soft lymphatic enlargements are said to respond well to iris. To attain positive results in hyperthyroid goitre, iris should be used for several months (8).

Skin

Iris is used as a detoxifying medicine to help clear excess waste products and toxins from the body that can contribute to inflammatory skin conditions. Herbalists may use iris for eczema and psoriasis both internally as a tincture or decoction, and externally in the form of a cream (2,12).

The British Herbal Pharmacopoeia recommends a combination of iris, burdock and echinacea in the treatment of boils and other cutaneous eruptions (14).

Musculoskeletal system

Iris is valuable as part of a wider treatment protocol for rheumatic conditions and toxic sciatica. These effects are secondary to its ability to help remove toxic waste products from the body, which in turn helps to reduce toxic load that can result in chronic inflammatory conditions such as those affecting the joints (2).

There is currently a lack of scientific research and clinical trials on iris. It has also not been well explored scientifically to identify the full spectrum of its bioactive constituents nor their medicinal effects (12). 

Animal studies are not condoned by Herbal Reality, however for the purpose of including research from which some understanding of therapeutic actions can be confirmed, some animal studies have been included referenced herein.

There is, however, one in vivo study that includes iris in a formula of other herbs; nutgrass (Cyperus rotundus) and indian elm (Holoptelia integrifolia). The study does not allude to the specific preparation or dosage of the three-herb formula. However, the results indicate a potential mechanism of action for assisting in weight management. The findings showed that the formula increased metabolic rate and enhanced lipolysis of stored fat in obese rats. The proposed mechanism explained by the study authors was activation of noradrenaline (15).

Many species of iris flowers were used to obtain the pigments ‘iris green’ and ‘iris blue’, which were used by medieval painters and manuscript writers. The roots of iris as used for medicine are referenced in historical texts as far back as the medieval times. It is described to have been blended with other herbs such as hyssop to treat skin conditions (16).

Iris is native to marshes, swamps, wet meadows, ditches and shorelines from Manitoba to Nova Scotia south to Virginia, Ohio, Illinois and Minnesota (18).

In the IUCN Red list of threatened species iris is classed as Least Concern, due to its widespread population. Whilst the report also found iris to be possibly declining in parts of its range, it is not thought that any global population decline is likely to meet (or be close to meeting) the threshold for vulnerable or threatened status (19).

Habitat loss and over-harvesting from the wild are two of the biggest threats faced by medicinal plant species. There are an increasing number of well-known herbal medicines at risk of extinction. We must, therefore, ensure that we source our medicines with sustainability in mind.

The herb supplement industry is growing at a rapid rate and until recent years a vast majority of medicinal plant produce in global trade was of unknown origin. There are some very real and urgent issues surrounding sustainability in the herb industry. These include environmental factors that affect the medicinal viability of herbs, the safety of the habitats that they are taken from, as well as the welfare of workers in the trade.

The botanical supply chain efforts for improved visibility (transparency and traceability) into verifiably sustainable production sites around the world is now certificated through the emergence of credible international voluntary sustainability standards (VSS). 

Read our article on Herbal quality and safety: What to know before you buy and Sustainable sourcing of herbs to learn more about what to look for and questions to ask suppliers about sustainability.

Herbal medicines are often very safe to take, however, it is important to buy herbal medicines from a reputed supplier. Sometimes herbs bought from disreputable sources are contaminated, adulterated or substituted with incorrect plant matter.

Some important markers for quality to look for would be to look for certified organic labelling, ensuring that the correct scientific/botanical name is used and that suppliers can provide information about the source of ingredients used in the product.

A supplier should be able to tell you where the herbs have come from. There is more space for contamination and adulteration when the supply chain is unknown.

Iris grows well in medium to wet soils in full sun to partial shade. The natural habitat of iris is in marshes, swaps and wet meadows so it can grow in 2–4 inches of shallow standing water (muddy or containers). 

Iris can be propagated by division after the plant has flowered. Wear gloves when dividing the rhizomes as contact with skin can cause irritation. After autumn, the leaves may be trimmed back to about 1 inch above the crown. Iris will form colonies if grown in the correct conditions, returning each year in spring.

For best results group iris in sunny areas of the garden in ponds or water features. Also may be grown in moist garden borders (18).

Iris root tincture

Tinctures are an excellent way to extract and preserve the medicinal properties of herbs. They are made using an aqueous-ethanolic solvent or in the making of home tinctures- often just an alcoholic spirit (brandy or vodka) are commonly used.

Ingredients

• Dried iris root
• 25–50% proof alcohol (e.g. vodka)
• Mason jar
• Mesh strainer or cheesecloth (muslin)
• Amber glass bottle
• Labels and permanent marker

Method

• Add the dried (chopped) iris root to the mason jar and cover with 250 ml of 50% alcohol.
• The fluid content in the herbal material will dilute the alcohol by around half and so it’s important for preservation that the alcohol stays above 20% proof.
• Label the jar with the date and ingredients.
• Leave to macerate (infuse) in a cool and dark place away from sunlight for between 2–4 weeks, gently shaking/ turning daily for the first week.
• Strain your tincture using the sterile mesh strainer or muslin cloth and place the liquid into your glass bottle.
• Label your tincture with the date and ingredients. Example: iris versicolor root tincture, fresh, 10th November 20XX, 1:2.5@25% ABV

1. Iris (Iris versicolor) — Monograph. Accessed 5th, August, 2024. Accessed at: The Sunlight Experiment. https://thesunlightexperiment.com/herb/iris
2. Hoffmann, D. 2003 Medical herbalism : the science and practice of herbal medicine. Healing Arts Press.
3. Wood M. The Earthwise Herbal : A Complete Guide to New World Medicinal Plants: Volume 2. Berkeley, Calif. North Atlantic Books; 2009.
4. Culpeper. 1995. Culpeper’s Complete Herbal. Great Britain: Wordsworth Editions Ltd.
5. Blue Flag (Iris versicolor). Restorative Medicine. https://restorativemedicine.org/library/monographs/blue-flag/
6. Bone K, Mills S. Principles and Practice of Phytotherapy: Modern Herbal Medicine. 2nd ed. Edinburgh Churchill Livingstone, Elsevier; 2013. https://ebookcentral.proquest.com/lib/think/detail.action?docID=1723553
7. Andrew S. Handbook of Constitutional and Energetic Herbal Medicine. Aeon Books; 2020.
8. University SC. Iris versicolor – Southern Cross University. www.scu.edu.au. https://www.scu.edu.au/analytical-research-laboratory—arl/medicinal-plant-garden/medicinal-plant-monographs/iris-versicolor.
9. Ellingwood F. 1919. American Materia Medica Therapeutics and Pharmacognosy. Cincinnati Ohio: Eclectic Medical Publications.
10. Felter HW. 1922. The Eclectic Materia Medica, Pharmacology and Therapeutics. Cincinnati Ohio: Eclectic Medical Publications.
11. Chevallier A. 2001. Encyclopedia of Medicinal Plants. St Leonards NSW: Dorling Kindersley.
12. Fisher C. Materia Medica of Western Herbs. Aeon Books; 2018.
13. Priest AW, Priest LR. Herbal Medication : A Clinical and Dispensary Handbook. The C.W. Daniel Company Ltd; 2000.
14. British Herbal Medicine Association. Scientific Committee. A Guide to Traditional Herbal Medicines : A Sourcebook of Accepted Traditional Uses of Medicinal Plants within Europe. British Herbal Medicine Association; 2003.
15. Bambhole VD;Kamalakar PL. Reduction of diet-induced obesity in rats with a herbal formulation. Ancient science of life. 2020;13(1-2). Accessed August 7, 2024. https://pubmed.ncbi.nlm.nih.gov/22556633/
16. Khatib S, Faraloni C, Bouissane L. Exploring the Use of Iris Species: Antioxidant Properties, Phytochemistry, Medicinal and Industrial Applications. Antioxidants. 2022;11(3):526. doi:https://doi.org/10.3390/antiox11030526
17. Therapeutic Research Centre. Natural Medicines Database. Iris versicolor. Naturalmedicines.therapeuticresearch.com. Published 2024. Accessed August 30, 2024. https://naturalmedicines.therapeuticresearch.com/databases/food
18. Iris versicolor – Plant Finder. www.missouribotanicalgarden.org. Accessed July 16, 2024. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=281141#:~:text=It%20is%20a%20marginal%20aquatic
19. Maiz-Tome L. IUCN Red List of Threatened Species: Iris versicolor. IUCN Red List of Threatened Species. Published June 30, 2015. Accessed August 6, 2024. https://www.iucnredlist.org/species/64315086/67729756