Herbs in History: Horsetail


Equisetum arvense L.


By Alain Touwaide & Emanuela Appetiti | January 2024

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Horsetail (Equisetum arvense L.)

Illustration 1: Horsetail (Equisetum arvense L.)

An archaeological vestige of the immemorial times when the plant world was in the making on the Earth—the time of the dinosaurs, if not before—, the genus Equisetum is now ubiquitous, with several species (Illustration 1).
Its graphic representations in manuscripts through the centuries attest to this strange, almost paradoxical nature. They show a non-plant, with just a simple, vertical stem, almost no leaves, no flowers, fruits or seeds, and a barely visible root. Interestingly enough, this representation of an ancestral type has been preserved with quite a high level of fidelity in the several societies that transmitted the legacy of the past one after the other, from Antiquity to the Renaissance.

A Difficult Genus

The paradox of horsetail does not stop there. As early as Antiquity, its therapeutic uses as currently assessed were already known. In the 1st century CE, indeed, the Greek Dioscorides described the plant—called hippouris in ancient Greek—and its uses as follows in his vast encyclopedia on the natural resources to be used for therapeutic purposes, the treatise De materia medica. The text as translated below aims to reflect the flavor of the Greek original (4.46-47):

Hippouris (= Horsetail). Some call it anabasion and others ephedron.
It grows in moist places and ditches.
Thin hollow stalks, reddish, slightly rough, solid, divided in joints one into the other; rush-like, thin, dense leaves all around [the plant].
It grows tall, leaning on nearby tree trunks, and it hangs spreading, with much dark foliage like horse's tails.
Root woody and tough.
The plant is astringent, wherefore its juice stops nosebleeds and helps against dysentery drunk with wine. It provokes urine.
The leaves ground and plastered close bleeding wounds.
The root and the whole plant help patients coughing, orthopnoeic, and with cuts.
The leaves drunk with water are reported to close intestinal ulcers, bladder cuts, and intestinal hernias.
There is also another horsetail having shorter, whiter, and softer foliage.
Ground with vinegar, this, too, treats wounds.

From a close analysis, the botanical description presents a contradiction between “rush-like, thin, dense leaves around [the stalks]” and “it hangs spreading with much dark foliage like horse's tails”, which seems to refer to two different species.

The illustrations in the ancient Greek and Arabic manuscripts do represent this contradiction, with a plant with short, thin leaves in small, dense bunches on the stalk (Illustrations 2-5) opposed to the other plant with “hanging” leaves looking indeed like a horse’s tail represented in a more or less stylized shape, according to the copies (Illustrations 6-7).

Other Horsetail in manuscript of Vienna

Other Horsetail in manuscript of Istanbul

Other Horsetail in manuscript of Vienna

Illustration 2: Other Horsetail in manuscript of Vienna, National Library of Austria, medicus graecus 1 (ca. 512, Constantinople), Dioscorides, De materia medica

Illustration 3: Other Horsetail in manuscript of Istanbul, Süleymaniye Kütüphanesi, Ayasofia 3702 (Baghdad [?], 13th cent.), Arabic translation of Dioscorides, De materia medica

Illustration 4: Other Horsetail in manuscript of Istanbul, Süleymaniye Kütüphanesi, Ayasofia 3703 (Baghdad [?], 1224 CE), Arabic translation of Dioscorides, De materia medica

Other Horsetail in manuscript of New York, NY

Horsetail in manuscript of Vienna

Horsetail in manuscript of Istanbul

Illustration 5: Other Horsetail in manuscript of New York, NY, New York Public Library, Spencer Collection, The New York Public Library Digital Collections, 1889 - 1890, Arabic translation of Dioscorides, De materia medica

Illustration 6: Horsetail in manuscript of Vienna, National Library of Austria, medicus graecus 1 (ca. 512, Constantinople), Dioscorides, De materia medica

Illustration 7: Horsetail in manuscript of Istanbul, Süleymaniye Kütüphanesi, Ayasofia 3702 (Baghdad [?], 13th cent.), Arabic translation of Dioscorides,
De materia medica


Horsetail in manuscript of Istanbul

Illustration 8: Horsetail in manuscript of Istanbul, Süleymaniye Kütüphanesi, Ayasofia 3703 (Baghdad [?], 1224 CE), Arabic translation of Dioscorides,
De materia medica

This suggests some confusion between two species. Latin Pliny (23/24-79 CE) spotted the problem in his encyclopedia of natural sciences (Naturalis Historia-Natural History) in his discussion about equisaetum.

Earlier in the same work (18.259), he explained the Latin name equisaetum:

… horsetail (equisaetum) named from its resemblance to horses' hair …

Further on (26.233), he established the equivalence between the Latin and Greek names:

Equisaetum, called hippuris by the Greeks …

He then pursued:

The Greeks hold various views about this plant … some call it hippuris, others ephedron, others anabasis. Their account is that it grows near trees, which it climbs and hangs down in many dark, rush-like hairs as if from a horse's tail; that its little branches are jointed, and its leaves few, slender and small …

There is no doubt that Pliny’s text refers here to Dioscorides’ chapter cited above (or its source), of which it is a translation.
In effect, one or more species of Equisetum could have been assimilated and possibly also confused with some species of Ephedra, particularly because the two genera might look similar to a non-botanical eye (Illustrations 9 and 10).

Horsetail, Equisetum arvense L. Ephedra

Illustration 9: Horsetail, Equisetum arvense L.

Illustration 10: Ephedra

It is probably significant that hippouris does not appear in the writings going back, or attributed, to the school of Hippocrates (460-between 375 and 350 BCE). It is mentioned, instead, in the botanical study by Theophrastus (ca. 371-ca. 287), Historia Plantarum (Inquiry into Plants), among the plants in the aquatic environment of the lake of Orchomenos in Greece (4.10.1), though under a different name (ipnos). Interestingly, Theophrastus adds that the plant grows in other places, stressing that it is identified with different names (4.10.2).
All this hints at a recent knowledge of the plant—that is, in Dioscorides’ time or in the sources that he used to compile De materia medica—possibly with some uneasiness and uncertainties.

Unambiguous Uses

The therapeutic uses help clarify these ambiguities. As we have seen, Dioscorides attributes a general property to hippouris: it is astringent. And he also lists the conditions for the treatment of which he recommends it, as well as its therapeutic actions. Both these conditions and actions can be divided into five major groups:

  1. hemorrhages
  2. dysentery
  3. diuresis
  4. conditions of the respiratory tract
  5. internal sections and cuts, and hernias

The general astringent property can account for the action on hemorrhages, probably in external use (the whole plant, the leaves, and the root, as per Dioscorides), for the treatment of nosebleeds, wounds, and cuts. This same property might also explain a symptomatic (and not etiologic) internal use of the juice of the plant with wine in cases of dysentery.

This might also be the case with the diuretic action. In ancient medicine, diuresis was understood as a consequence of astringency in a mechanical way: the constriction of tissues resulting from astringency was considered to provoke the elimination of the liquid contained in the tissues. Although Dioscorides does not explicitly specify the mode of administration, it can reasonably be assumed it was in internal use of the whole plant, possibly with wine as for dysentery.
The administration of the leaves in internal use with water for the treatment of hernias might be accounted for by the same mechanism. The astringent action might have led to speculation that a constriction could help to reduce hernias by reinforcing (or closing) the tissues containing the intestines, the relaxation or perforation of which might have provoked a hernia.
The other indications (for the respiratory tract, with cough and orthopnoesis) and internal ulcers and sections (intestines and bladder) probably result from empirical uses that have not been rationalized and accounted for by either the explicitly stated astringent action or any other.
Whatever their rationalization in ancient medicine, these indications are found in contemporary phytomedicine. Equisetum is identified, indeed, as an astringent and used for the treatment of tuberculosis, kidney affections, inward ulcers, and skin conditions with bleeding in Meyers’ Pflanzliche Therapie (Plant Therapy) first published in 1935. Also, in Madaus’ vast compilation of traditional therapeutic uses of plants published three years later (1938, Lehrbuch der biologischen Heilmittel-Manual of biological remedies), Equisetum is described as the agent par excellence for the treatment of tuberculosis (even with internal hemorrhages) and kidney pathologies. Its astringent action is clearly stated and recommended to stop all kinds of wounds, and to treat diarrhea.
Returning to the description of hippouris, the correspondence of its therapeutic indications in Dioscorides and present-day practice allows to consider that Equisetum species were known and possibly judiciously used in Antiquity, even though there might have been some confusion between species, and possibly also between genera in the description of the plant.

Two species of equisetum

Illustration 11: Two species of equisetum in Pietro Andrea Mattioli, Commentarii in Dioscoridies Libros Sex, 1560, p. 514


Confirmation from Tradition

If there still were a doubt, tradition, which acts as a constant and repeated clinical trial, confirms the usages of hippouris as above and, by way of consequence, also its identification.

In the 10th / 11th century and the Arabic World, ibn Sina (Avicenna) (980-1037 CE) defines it as an astringent plant beneficial for bleedings, healing wounds and ulcers, and reducing swollen stomach and enterocele.
The Old English Herbal possibly going as far back as Avicenna’s time follows suit, reproducing Avicenna’s use for bloated stomach and Dioscorides’ recommendations about the affections of the respiratory tract, apparently tuberculosis (chapter 40):

If a person has a bloated stomach: take the juice of this plant, which the Greeks call hippirum and the Italians call equisaeta, in sweetened wine; give two cups of it to drink. It is firmly believed that it will heal the complaint.
If a person should cough up much blood: take the juice of this same plant; simmer in strong wine without letting it steam; have him drink it while fasting. It will soon staunch the blood.


Four species of equisetum

Four species of equisetum

Four species of equisetum

Four species of equisetum

Illustration 12-15: Four species of equisetum in Pietro Andrea Mattioli, Commentarii in Dioscoridies Libros Sex, 1565, pp. 1026, 1027, 1028 and 1029, respectively

The same four species of equisetum

Illustration 11: Two species of equisetum in Pietro Andrea Mattioli, Commentarii in Dioscoridies Libros Sex, 1560, p. 514

Interestingly, tradition also preserved the ancestral appearance of the plant and, possibly also, the uncertainty in its botanical description as the many illustrations in the translation of, and commentary on, Dioscorides, De materia medica by the Italian physician Pietro Andrea Mattioli (1501-1578) confirm. After two small size representations on one page in the 1560 edition of the work (Illustration 11), Mattioli offered large, full-page images in the 1565 edition with no less than four species, real or supposed (Illustrations 12-15), and returned to smaller images, grouped together on the same page in 1570, with only two species (Illustration 16).

Contrary to his usual prolixity, Mattioli does not elaborate about the four images he provides in the 1565 and 1570 editions. In his commentary, he treated them together, leaving the reader with these images of a fern-like plant that probably did evoke ancestral times in a significant way. And he did not even spot the contradiction that we have stressed in the description of the foliage of hippouris, most probably because he was not at ease with this plant apparently ancestral in nature.


European Medicines Agency
2 February 2016
Committee on Herbal Medicinal Products (HMPC)
European Union herbal monograph on Equisetum arvense L., herba
2 February 2016
Committee on Herbal Medicinal Products (HMPC)
Assessment report on Equisetum arvense L., herba
Scientific articles
Sureshkumar J. et al. 2023. Genus Equisetum L: Taxonomy, toxicology, phytochemistry and pharmacology. Journal of ethnopharmacology 314 (2023), 116630.
Makia R. et al. 2022. In Vitro Cytotoxic Activity of Total Flavonoid from Equisetum arvense Extract. Reports of biochemistry & molecular biology 11(3) (2022), pp. 487–492.
Boeing T. et al. 2021. Phytochemistry and Pharmacology of the Genus Equisetum (Equisetaceae): A Narrative Review of the Species with Therapeutic Potential for Kidney Diseases. eCAM - Evidence-based complementary and alternative medicine 2021, 6658434.
Christenhusz M. et al. 2021. Biogeography and genome size evolution of the oldest extant vascular plant genus, Equisetum (Equisetaceae). Annals of botany 127(5) (2021), pp. 681–695.
Clark J.W., M.N. Puttick, P.C.J. Donoghue 2019. Origin of horsetails and the role of whole-genome duplication in plant macroevolution. Proceedings. Biological sciences 286(1914) (6 November 2019), 20191662. https://doi.org/10.1098/rspb.2019.1662
Steinborn C. et al. 2018. In Vitro Anti-inflammatory Effects of Equisetum arvense Are Not Solely Mediated by Silica. Planta medica 84(8) (2018), pp. 519–526. https://doi.org/10.1055/s-0043-123075
Elgorriaga A. et al. 2018. Origin of Equisetum: Evolution of horsetails (Equisetales) within the major euphyllophyte clade Sphenopsida. American journal of botany 105(8) (2018), pp. 1286–1303.
Al-Snafi A. E. 2017. The pharmacology of Equisetum arvense - A review. IOSR Journal of Pharmacy 7(2) (February 2017) Version. 1, pp. 31-42. https://www.iosrphr.org/papers/v7i2V1/D0702013142.pdf
Asgharikhatooni A. et al. 2015. The effect of equisetum arvense (horse tail) ointment on wound healing and pain intensity after episiotomy: a randomized placebo-controlled trial. Iranian Red Crescent medical journal 17(3) (2015), e25637.
Carneiro D. et al. 2014. Randomized, Double-Blind Clinical Trial to Assess the Acute Diuretic Effect of Equisetum arvense (Field Horsetail) in Healthy Volunteers. eCAM - Evidence-based complementary and alternative medicine: 2014, 760683.
Asgarpanah J., E. Roohi 2012. Phytochemistry and pharmacological properties of Equisetum arvense L. Journal of Medicinal Plants Research 6 (2012), pp. 3689-3693.
Ortega García J. A. et al. 2011. Prenatal exposure of a girl with autism spectrum disorder to 'horsetail' (Equisetum arvense) herbal remedy and alcohol: a case report. Journal of medical case reports 5 (2011), 129. https://doi.org/10.1186/1752-1947-5-129
Mimica-Dukic N. et al. 2008. Phenolic compounds in field horsetail (Equisetum arvense L.) as natural antioxidants. Molecules (Basel, Switzerland) 13(7) (2008), pp. 1455–1464.

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