# Rosebay willowherb (Epilobium angustifolium)

*Rose bay willow, fireweed, great or spiked willow-herb, flowering willow, French willow, Persian willow, blood vine, blooming Sally, purple rocket, wickup, wicopy; Ivan tea, Kapor tea; *Epilobium angustifolium* L.; *Chamaenerion angustifolium* (Scop.); in pharmacy *Epilobii herba*, with the small-flowered *Epilobium parviflorum* Schreb.*

**Known today as.** *Epilobium angustifolium*, of the family Onagraceae, which Grieve calls “one of our handsomest wild flowers”: tall erect stems four to eight feet high, densely clothed with long, narrow leaves, ending in long spikes of light rose-purple flowers. The pods split into four strands to free tiny seeds borne on silky white hairs that the slightest wind scatters. In America, Grieve notes, it springs up on ground cleared by fire, hence ‘fireweed’; in Ireland ‘blooming Sally’ is a corruption of *Salix*, the willow, for its willow-like leaves.

Kind: Plant

> **Caution.** Men using it should see a doctor if symptoms worsen, or if fever, spasms, blood in the urine, painful urination, or retention of urine occur. Green’s *Universal Herbal* of 1832, quoted by Grieve, reported that an infusion of the plant “produces a stupifying effect.”

## What was it used for?

An astringent herb and a tea. Grieve gives the roots and leaves as demulcent, tonic, and astringent, used in domestic medicine “in decoction, infusion and cataplasm,” much in America as an intestinal astringent, and recommended for whooping cough, hiccough, and asthma. The European Medicines Agency’s assessment report adds that Native Americans used the roots and aerial parts outwardly for skin infections and rectal bleeding, and that in Russia the leaves, plain or fermented, were drunk as ‘Ivan tea’ or ‘Kapor tea’ for stomach ulcers, gastritis, and sleeplessness.

## What does modern science say?

The European Medicines Agency’s herbal committee accepts the herb of *E. angustifolium* and of the small-flowered *E. parviflorum* as a traditional herbal medicine, “exclusively based upon long-standing use,” for the relief of lower urinary tract symptoms of benign enlargement of the prostate, after a doctor has excluded serious conditions (monograph of 2015). That use, its assessment report explains, became popular in Austria, Germany, and Poland after Maria Treben’s books on herbal remedies, from 1978, which sold more than eight million copies; Treben recommended only the small-flowered willowherbs and considered *E. angustifolium* not to be effective, yet it too was marketed from the 1980s. The report finds 4 to 14 per cent of tannins, oenothein B among them, with phenolic acids, sterols, and triterpenes, and found no clinical data from which to draw any conclusion on efficacy.

## Pharmacognosy and toxicology

- **oenothein B**: among the tannins, which make up 4 to 14 per cent
- **tannins**: 
- **sterols**: 

**Mechanism.** Not established in the sources read for this entry.

**Standing.** European Union herbal monograph (2015): traditional use, “exclusively based upon long-standing use,” for lower urinary tract symptoms of benign prostatic enlargement.

## What lore surrounds it?

When the old buildings on the site of Kingsway and Aldwych in London were pulled down, Grieve writes, the cleared ground was covered the next summer by rosebay willowherb “as by a crimson mantle, though no one could explain where the seeds had come from.” In Kamchatka, after Green’s *Universal Herbal*, the dried pith was boiled into a sweet ale, made more intoxicating still with the fly agaric.

## What did the older authorities say?

**Gerard, as Grieve records.** Gerard called it “A goodly and stately plant having leaves like the greatest willow or osier, garnished with brave flowers of great beautie,” and grew plants received from Yorkshire, apparently as a rarity, “which doe grow in my garden very goodly to behold, for the decking up of houses and gardens.” By Grieve’s day it had become more common.

## Sources

- Grieve, M. *A Modern Herbal*, “Willow-Herbs.” As published on botanical.com.
- European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Epilobii herba (Willow herb)*. EMA/HMPC/712511/2014, 24 November 2015.
- European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Epilobii herba*. EMA/HMPC/712510/2014, 24 November 2015.
- European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Epilobii herba (Willow herb)*. EMA/HMPC/712511/2014, 24 November 2015.
- European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Epilobii herba*. EMA/HMPC/712510/2014, 24 November 2015.

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*Rosebay willowherb.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-16. The Thinking Press. https://thethinkingpress.org/materia-medica/rosebay-willowherb

Historical description, not medical advice.