Blue Flag (Iris versicolor)


Goiter (may be administered both topically and internally), sluggish metabolic function, detoxification (especially the thyroid gland), promote movement of sluggish body fluids including saliva, lymph, bile, and digestive secretions.

Mechanism of Action

Iris contains iridin, an isoflavone. Iridin is the 7-glycoside of irigenin that can be isolated from several species of Iris. The plant also contains volatile oils, resins, and alkaloids that have not yet been investigated.

Iris is a supportive herb for thyroid function.

Evidence-Based Research

Although there is little to no modern research on Iris for thyroid function, the bulbs were used and written about extensively by the early American “eclectic” physicians, a group of medical doctors practicing in the late 1800s and early 1990s who recommended the plant for goiter and to decongest and detoxify atonic tissues.

There are no human clinical studies on Iris, but animal studies using a trio of herbs including Iris versicolor have shown the formula to promote weight loss via increased metabolic rate1 and enhanced lipolysis of stored fat.2 The proposed mechanism by the study authors was activation of noradrenalin in obese rats.3

Safety in Pregnancy and Breastfeeding

There are no published data.

General Safety

There are no published data.


There are no published data, but because iridin is potentially irritating to mucous membranes, Iris preparations are usually used in fairly small dosages and are often mixed with other plants to prevent oral or digestive irritation. Many formulas dose just 100–200 mg at a time.

Traditional Uses

Iris bulbs have been used traditionally for goiter, both topically and internally, to improve sluggish metabolic function and to move bodily fluids including saliva, lymph, bile, and digestive secretions. The bulk of the early 1900s era literature purports that Iris mainly decongests and detoxifies tissues, including the thyroid, so that normal functioning can be restored.



Anc Sci Life. 1993;13(1–2):89–96. Reduction of diet-induced obesity in rats with a herbal formulation.
Bambhole VD, Kamalakar PL.

2 Anc Sci Life. 1988;8(2):117–24. Effect of some medicinal plant preparations of adipose tissue metabolism. Bambhole VD.

3 The Complete Botanical Prescriber. 3rd Edition. 1993. p129. Iris versicolor. Sherman JA.