# Alder buckthorn (Rhamnus frangula)

*Black dogwood, black alder, frangula bark, German *Pulverholz*; *Rhamnus frangula* L.; *Frangula alnus* Mill.; in pharmacy *Frangulae cortex**

**Known today as.** *Rhamnus frangula*, a slender shrub of the family Rhamnaceae, widespread in Europe and northern Asia and found in English woods and thickets, rare in Scotland. Grieve distinguishes it from the common buckthorn by its more tree-like habit, the absence of thorns, its entire, feather-veined, alternate leaves, and its berries with only two or three seeds. The drug is the bark, papery young quills grey or blackish-brown outside with small whitish warts, crimson beneath when scraped, sweetish and slightly bitter, colouring the saliva yellow when chewed.

Kind: Plant  
Poisoning: The anthranoid purgatives (https://thethinkingpress.org/materia-medica/poisons/anthranoid)

> **Caution.** A stimulant laxative, for short use only, with the same cautions as the other anthranoid laxatives: long use may impair the bowel’s function and bring dependence and loss of water and potassium. Not in pregnancy or breast-feeding, not under twelve, and not with bowel obstruction, inflammatory bowel disease, appendicitis, unexplained abdominal pain, or severe dehydration; potassium loss can strengthen cardiac glycosides. The fresh bark, Grieve warns, is an irritant poison to the gut.

## What was it used for?

A gentle laxative. Grieve calls it tonic, laxative, and cathartic, given chiefly as a fluid extract “as a gentle purgative in cases of chronic constipation,” and useful for piles; the milder alder buckthorn’s bark, she writes, proved a satisfactory substitute for the violently acting berry juice of the common buckthorn, though the much-advertised cascara sagrada had largely taken its place, “though itis a less agreeable aperient.”

## What does modern science say?

The European Medicines Agency’s herbal committee accepts the bark on clinical evidence, as ‘well-established use,’ for short-term use in occasional constipation (monograph of 2019). Its assessment report requires at least 7 per cent of glucofrangulins, the emodin glycosides held responsible for the action, and explains that in the fresh bark they are in a reduced form and in stored bark oxidised, which is why the bark is stored. It found no recent clinical studies of frangula bark alone in constipation, the laxative effect resting mainly on pharmacological data, expert opinion, and clinical experience.

## Pharmacognosy and toxicology

- **glucofrangulins**: the emodin glycosides held responsible for the action; at least 7 per cent required, reduced in the fresh bark and oxidised in stored bark

**Mechanism.** A stimulant laxative of the anthranoid kind; its assessment report rests the effect mainly on pharmacological data, expert opinion, and clinical experience.

**Standing.** European Union herbal monograph (2019): well-established use, for short-term use in occasional constipation.

## What lore surrounds it?

Stripped of its bark, the wood makes a very light, inflammable charcoal, preferred by gunpowder makers, who named the shrub black dogwood; in Germany, for the same reason, it is *Pulverholz*, powder-wood. The bark and leaves gave a yellow dye much used in Russia, and the berries green, blue, and grey. Folkard records that the Mongols made their idols of its wood, for its rich hue.

## What did the older authorities say?

**Grieve, *A Modern Herbal* (1931).** “Dried seasoned bark from one to twoyears old alone should be used, as the freshlystripped bark acts as an irritant poison on the gastro-intestinal canal.” Kept for a length of time, she says, its action becomes gradually less violent “and more like that of rhubarb.” Lozenges of it were dispensed as ‘Aperient Fruit Lozenges.’

## Sources

- Grieve, M. *A Modern Herbal*, “Buckthorns.” As published on botanical.com.
- Folkard, R. (1884). *Plant Lore, Legends, and Lyrics*, “Buckthorn.” Project Gutenberg, 44638.
- European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Frangulae cortex (Frangula bark)*. EMA/HMPC/726261/2016, 25 September 2019.
- European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Frangulae cortex*. EMA/HMPC/483550/2018, 25 September 2019.
- European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Frangulae cortex (Frangula bark)*. EMA/HMPC/726261/2016, 25 September 2019.
- European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Frangulae cortex*. EMA/HMPC/483550/2018, 25 September 2019.
- Grieve, M. *A Modern Herbal*, “Buckthorns.” As published on botanical.com.

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

Historical description, not medical advice.