Iris versicolor

Iris versicolor

Common names:
Blue Flag (1-4); Water Flag (5, 6); Wild Iris (3)
Part(s) used:
Rhizome (1-4)


Perennial up to 1 m; erect stems, sword-shaped leaves; 2-3 blue to violet flowers per stem (3); yellow and white markings at base of sepals (5); dried rhizome is cylindrical or flattened, externally greyish, internally reddish-brown, with annular joints, cupped-shaped stem scars, ring-shaped leaf scars and root scars on the under surface (8).
Habitat: Native to wetlands of east and central North America (3, 5, 8); prefers damp and marshy areas in the wild but cultivated as an ornamental garden plant around the world (3, 8); likes loamy or peaty soil (5).


Traditional data is the main source of information on Iris versicolor.

Finley Ellingwood reported that Iris was considered useful in cases of jaundiced inactive skin (liver), light coloured stools (bile) and low urine flow.
It was also recommended when the signs of irritable mucous membranes of the GIT were present, such as nervous pain over one eye or the right side of the face (generally), nausea or vomiting with stomach pain, gastric pain after a fatty meal, diarrhoea with a burning sensation or lower abdomen pain (9).
The oleoresin was used in liver and intestinal conditions including dropsy (oedema from Congestive Heart Failure).
All causes of chronic jaundice could be treated with Iris.
Iris helped the healing of stomach conditions causing headache and migraine.

It seemed very potent as an anti-syphilitic where the lymph glands were inactive, in the treatment of skin conditions such as psoriasis, eczema, purulent and open ulcers and in thyroid conditions such as goitre (9).
H W Felter reported similar findings and added that in high doses it could be a violent emetic with acid vomitus, watery catharsis, colic and rectal heat. It can even cause gastro-enteritis to the point of death.
Iris is an ideal remedy for all conditions of ‘bad blood’ and poor nutrition, indicating an inefficient lymphatic drainage rather than being directly related to the quality of the blood itself.
In thyroid disorders such as goitre its acts mainly in reducing swelling and has no effect on tachycardia and other signs of hyperthyroidism. Soft lymphatic enlargements respond well to Iris whereas hard enlargements respond better to Phytolacca. To attain positive results in goitre, Iris should be used for several months.
Very small frequent doses of Iris are used in painful gastric irritation and dysentery and in these cases Iris seem to be more potent than Ipecacuanha.
Only the heavy, resinous rootstocks are effective as the old, light coloured Iris has no therapeutic effect(7).

King’s American Dispensatory reports that the physiological effects of Iris versicolor are mainly upon the GIT, glandular and nervous systems and act by exciting the biliary, pancreatic and salivary secretions. It was also used as a gland and liver remedy by the Physiomedicalists (3).
In small doses at short repeated intervals, it acts on the whole GIT, but in large doses it evacuates and exhausts the system by acting on the liver. It produces neuralgia of the face, head and the extremities through its effects on the nervous system.
Iris causes salivation without hurting gums and teeth and is often mistaken with mercury poisoning which causes spongy gums and loose teeth.
Therapeutically Iris is a cholagogue and an alterative and is one of the best remedies to influence waste and repair by acting on the liver, pancreas, kidneys and lymphatics (10).

Culpeper considers Iris as a hot and dry (2nd degree) remedy that strengthens and stops discharges of the stomach and regularises heavy menses when taken in small dose every morning mixed with red wine (6).

Iris was a frequently used remedy by Native Americans, as an emetic, cathartic, and diuretic; to treat wounds, earache, cold and cholera (3). They ingested the steamed root for immune protection (2).

Iris was cultivated by the Creek American Indians as a cathartic and bowel remedy. The Albany Indians crushed its root in a powder and made a poultice for leg ulcers. The Meskwakis used the roots as decoction for cold and lung problems. The Ojibwa used it as an emetic and it was the most precious medicine of the Penobscots (11).
Colonel Lydius notes that the American Indians wash the root, boil it shortly then crush it between stones. They use this paste on ulcers and bath the leg with the water in which the root is boiled (1).

Iris was combined with Rumex crispus and Smilax ornata (Sasparilla) as a lymph cleanser.
Henry Smith reported successful use of Iris in congested and obstructed lymphatic conditions as these indicate the beginning of chronic skin diseases (1).

It was also used as an alternative by colonial settlers and homoeopaths used it as low potency for GIT, liver, pancreas and nervous system (migraine) disorders (12).

Kerry Bone adds that Iris was also traditionally used for muscular pain arising from gastric conditions, for enlarged uterus or ovary, dysmenorrhoea, prostate discharge and nocturia, as well as for ‘morning sickness’.
It is an emetic in large doses but an anti-emetic in small doses.
Iris versicolor was officially listed in the USP (United States Pharmacopoeia) from 1820 to 1895 (2).

Major Active Constituents

Tripernoids (iridin, iridals) (3, 13); oleoresin (3-5, 8, 13); salicylic acid (3-5, 8); isophthalic acid (3, 8); alkaloids (4, 5, 8); tannins (3-5, 8); small amount of volatile oil (0.025%) as furfural (3, 5, 13).


  • Lymphatic (1, 2, 7-9, 13)
  • Cholagogue (1-4, 7-9, 13, 14)
  • Diuretic (1-5, 8, 9, 13, 14)
  • Laxative (1-5, 7-9, 13, 14)
  • Anti-inflammatory (1, 4, 14)
  • Astringent (liver) (1)
  • Depurative (2, 13)
  • Stimulant (1)
  • Anti-emetic in small doses (1, 14), emetic in large doses (3, 5, 7, 9)
  • Alterative (1, 9)
  • Restores loss of tonicity to involuntary muscle structures (1).


The plasma levels of free fatty acid and glycerol were significantly increased after an oral administration of 20 mg/kg of Iris versicolor in an experimental model. This demonstrated the ability of Iris to mobilize fat tissue (2).

Clinical Outcome Studies

There are no clinical studies on Iris versicolor (2).


Current Use:

  • Chronic skin, liver and gallbladder disorders (1-3, 5, 7-10, 14)
  • Headache, migraine (1, 2, 9, 10)
  • Constipation (1, 2, 5, 10, 13)
  • Poor digestion (2, 5-7, 9, 10)
  • Enlarged lymph glands, thyroid, spleen (1-3, 6, 7, 9, 10)

Traditional Uses:
Duodenal catarrh with jaundice and light coloured stools; cholera infantum and morbus; diarrhoea and dysentery (small dose); gastralgia (small dose); oral aphth; reflex muscular pain involving viscera of GIT and pancreas; goitre and any soft glandular enlargement; ovary and uterine disorder; chronic renal disease, ascites, anasarca, hydrothorax, or hydropericardium; dropsy (high dose); leucorrhoea, dysmenorrhoea; rheumatism, gonorrhoea, spermatorrhoea, prostatorrhoea; dermal conditions such as syphilis, herpes zoster, rupia, impetigo, lepra, pustules of face and scalp (7, 9, 10).

Iris was also traditionally combined as a remedy with mandrake (Podophyllum peltatum), poke root (Phytolacca decandra), black cohosh (Cimicifuga racemosa), sarsaparilla (Smilax spp.) and yellow dock (Rumex crispus) for various conditions (15).

Contra-indications and Cautions

  • None known (13)
  • In pregnancy: no evidence of foetal damage in animal studies (Category B); No malformation or other harmful effects on foetus from use in women (Category B) (13)
  • Compatible with breastfeeding (Category C) (13)
  • Can irritate the digestive system and cause vomiting in large doses (3, 8) indicating the plant has some minor toxicity, however;
  • No reliable human studies have shown any toxicity in using Iris versicolor (13, 15), and;
  • No incident of over-dose in humans are known (13).


Note: Only the fresh rhizome should be used topically. Fresh rhizome should not be taken internally as it will cause vomiting (15).
For above conditions use Iris as:
Decoction: 2.5-5.0g of dried rhizome into a cup of water, bring to a boil. Simmer 10-15 min. Drink three time a day (4); 1.8-6g/d (13); 0.5-2g/d (8);
Tincture: 3-6ml/d of 1:2 (2, 13); 2-4ml tds (4); 3.55-10.65ml/d (5); 3.55ml/d in red wine (6)

For the eclectics, dosage depends largely on the effect desired (10):
0.32-0.97 g or 0.62-3.7 ml of the tincture for GIT and glandular secretions.

If large doses are to be taken, Iris can be taken with a few grams of capsicum, ginger, camphor or blue cohosh to avoid the side effects of nausea and vomiting (10, 15).


1. Bartram T. 1995. Bartram's Encyclopedia of Herbal Medicine. London: Robinson.

2. Bone K. 2003. A Clinical Guide to Blending Liquid Herbs. St Louis, Missouri: Churchill Livingstone.

3. Chevallier A. 2001. Encyclopedia of Medicinal Plants. St Leonards NSW: Dorling Kindersley.

4. Hoffmann D. 1996. The Complete Illustrated Holistic Herbal. Shaftesbury, Dorset: Element Books.

5. Grieve. 1931. A Modern Herbal. Surrey: Random House Publishers Ltd.

6. Culpeper. 1995. Culpeper's Complete Herbal. Great Britain: Wordsworth Editions Ltd.

7. Felter HW. 1922. The Eclectic Materia Medica, Pharmacology and Therapeutics. Cincinnati Ohio: Eclectic Medical Publications.

8. Mills S. 1985. The Complete Guide to Modern Herbalism. London: HarperCollins Publishers.

9. Ellingwood F. 1919. American Materia Medica Therapeutics and Pharmacognosy. Cincinnati Ohio: Eclectic Medical Publications.

10. Felter H W & Lloyd J U. 1983. King's American Dispensatory. 18th ed. Sandy Oregon: Eclectic Medical Publications.

11. Griggs B. 1997. New Green Pharmacy - The story of western herbal medicine London: Vermilion.

12. Wood M. 1997. The Book of Herbal Wisdom. Using Plants as Medicines California: North Atlantic Books.

13. Mills S, Bone K. 2005. The Essential Guide to Herbal Safety. St Louis, Mo: Elsevier Churchill Livingstone.

14. Association BHM. 1979. British Herbal Pharmacopoeia. British Herbal Medicine Association.

15. Iris versicolor. Natural Standard. 2008. Natural Standard Monograph. Davis M, Bryan J K, Edmondson A, Giese N, Weissner W. Accessed 22 September 2008. <>


This monograph was authored in 2008 by Benoit Vaessen, a student in Southern Cross University’s Bachelor of Naturopathy programme, and edited by Nena Aleschewski BNat. While the author and editor have strived to cite published information accurately, Southern Cross University will not be responsible for any inaccuracies that may have occurred.

This information is provided for educational purposes only and does not constitute medical advice. If you wish to use herbal medicine as part of your health care, seek the advice of an appropriately qualified practitioner.