Herbs in History: Fennel


Foeniculum vulgare Mill.


By Alain Touwaide & Emanuela Appetiti | December 2022

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Snake’s Sight

When athletes run a marathon (26.2 miles), they re-enact the exploit by the Greek soldier Pheidippides who ran from Marathon to Athens in 490 BCE to announce the victory of the lightly armed Athenian troops on the heavy infantry of the Persian king Darius I, who was trying to invade and conquer Greece. Marathon runners probably do not know that the battle took place in a region where fennel (marathon in ancient Greek) grew abundantly, giving its name to the area as the fennel field (Illustration 1).

Marathon in Greece (Google Maps)

Illustration 1: Marathon in Greece (Google Maps)

An Ancient Tradition

The origin of the ancient Greek name of fennel means a plant growing high. It probably refers to individuals of a much taller size than our cultivated ones, with also larger stalks (up to 3 inches). These stalks are full of a pith that inflames easily and smolders slowly, without burning the stalks themselves. Once emptied in that way, the hollow stalks were used in Antiquity in the way of a quiver. As a mythological tale goes, it is in a stalk of fennel prepared in that way that Prometheus hid the fire that he stole from Zeus to give it to humans and allow them to start modern life.
This narrative, which brings us back to the mythological origins of civilization, clearly suggests that knowledge and use of fennel go far back in time in Mediterranean history. The very name of fennel in Greek is believed to have been borrowed from a language that has not been precisely identified, indicating that the plant was not originally native to the Greek World. At any rate, it is already present at the eve of the Greek World as it appears on a Mycenaean tablet dating to the 13th century BC, among a list of spices.
The most ancient botanical description of fennel appears in the famous Historia Plantarum (Inquiry into Plants) by the Father of Botany, Theophrastus (4th/3th cent. BC). There fennel  is unmistakably described as a ferula, with the typical umbels that gave its name to the former family of Umbelliferaceae now idenfied as Apiaceae (Illustration 2). Originally identified by Linnaeus as Anethum foeniculum L., fennel is now identified as Foeniculum vulgare Mill. (=Foeniculum officinale All.). In both the Linnean and the current name, the term foeniculum comes from classical Latin, meaning “small/thin hay”, probably in reference to the small leaves of fennel. The natural habitat of fennel is close to the sea, but not on the sea-shore, or, as in the specific case of Marathon, close to a marsh.  

Fennel with its typical structure

Illustration 2: Fennel with its typical structure 

Wild fennel in the manuscript of Padua, Seminario

Illustration 3: Wild fennel in the manuscript of Padua, Seminario, 194, f. 63 verso (Courtesy Seminario Vescovile, Padova, Italy)

After it was introduced to the south-east Mediterranean, fennel has been widely propagated. Whereas it originally was a wintery species it is now available all year round in a cultivated form.
Fennel appears in the most ancient Greek medical literature that has been preserved, the writings attributed to the Father of Medicine, Hippocrates (5th/4th century BCE). In this series of texts, fennel is mentioned in no less than 30 formulae for medicines, which is a significant number.
Characteristically enough, almost all are in the oldest works of the Hippocratic Collection, which are devoted to gynecology and date back to the time of the birth of the historical Hippocrates. In addition to various conditions of the womb (including the so-called hysteria), fennel is prescribed as an emmenagogue and a galactogen, in addition to the treatment of female infertility and the post-partum cleaning of the uterus.
In three non-gynecological treatises of the Hippocratic Collection fennel has different uses that attest to trials aimed to expand its applications beyond gynecology. One such indication is in a treatise on Diseases. There, fennel is used for the treatment of a severe affection of the respiratory tract with high fever, shivering, cough, breathing difficulty, pain in the back and the flanks, and hematuria followed by death a couple of days later. In Internal affections, possibly written at the turn of the 5th/4th centuries, fennel is administered against icter. And, in another treatise of the 5th or 4th century devoted to the analysis of the alimentary and medicinal properties of foodstuffs (Regimen), fennel is listed among plants credited with a diuretic action without any further explanation.
Several centuries later, in the 1st century AD, we find fennel in the largest encyclopedia on materia medica compiled in Antiquity, De materia medica by the Greek Dioscorides. Contrary to his usual way, Dioscorides did not describe fennel in the chapter he devoted to it, indirectly indicating through this omission that the plant was well known. In the manuscript copies of the work that have survived, fennel is nevertheless represented in an illustration that exactly captures its typical botanical structures and allowed for learning and identification in the past (Illustration 3).
It is worth citing Dioscorides’ full list of the therapeutic uses of fennel as it distinguishes in a very methodical way the different parts of the plants, their state (fresh or dried) and their preparation, and the medical conditions for which each of them was used. Although the translation of the original Greek text below modifies the structure of the original text (which is in a discursive form in the original and not as a list as below), it respects the sequence of the indications in the text which distinguished the parts of the plant:

  1. Its herbaceous part, when eaten, can produce milk.

  2. So does also the seed taken as a beverage or cooked with barley gruel.

  3. The decoction of its foliage taken as a beverage:

a) is suitable for nephritics and the conditions of the bladder, being diuretic.
b) is given with wine to patients bitten by snakes.
c) brings the menses.
d) relieves nausea and heartburn, when drunk with cold water in feverish states.

  1. The roots ground with honey and smeared treat patients bitten by rabid dogs.

  2. The juice obtained from the stalks and leaves and dried in the sun, is efficacious in all the eye medicines to sharpen the vision.

  3. The seed, too, when still green, is juiced for the same remedies with the leaves and the extremities of the branches, and also the root at its first growth.

Some of Dioscorides’ uses reproduce ancient Hippocratic ones. Fennel is described here as galactogen (nr. 1 and 2 above) and emmenagogue (nr. 3, c) as in the oldest gynecological Hippocratic treatises. Building on Hippocratic medicine, Dioscorides goes beyond. While he states, indeed, that fennel is diuretic as did the Hippocratic writing on Regimen cited above, it infers that this activity is beneficial for the treatment of patients suffering of kidney and bladder conditions (nr 3, a).
As the latter application already indicates, Dioscorides’ treatise expands on the ancient uses. This is the case of the administration of fennel to treat bites by snakes not better identified (nr 3, b). The ancient literature on venomous animals and envenomation always clearly distinguishes neutotoxic and hemolytic venoms, which is not the case here. We can thus guess that reference is made here to non-venomous bites. The interesting point is the association of this use against bites with an emmenagogue action (nr 3, b and c). We may hypothesize that the administration of fennel to victims of snake bites is justified by the hemorrhagic action characteristic of the emmenagogues in ancient literature. In that case, fennel is preventative in the treatment of snake bites, to eliminate possible infectious agents injected into the flesh through the bite. We do not know, however, whether this was an internal or external use. The case of the rabid bites (nr 4) in Dioscorides could help to clarify. The administration in this case could rely on the same principle as for the snake bites, that is, the hemorrhagic action. In the case of the rabid dog, however, the way of administering fennel is explicitly indicated: it is applied externally, on the wound, possibly to provoke a local, micro-hemorrhage aimed to eliminate the venom supposedly injected by rabid dogs according to ancient medicine.


A Snake’s Lesson?

The ophthalmological use in Dioscorides (nr 5) is new, instead. It is certainly significant that it is the indication with the most developed mode of preparation in Dioscorides’ chapter. The novelty of this use raises interesting questions, mostly its origin. Was it the result of theoretical research, proceeding by reasoning on the basis of the other uses? Was it discovered by trial and error? Does it come from an earlier medical work that is now lost? Or has it another source that we do not identify?
A search in the ancient literature on natural history brings to light a relevant information. Dioscorides’ opthalmologic usage of fennel reminds us of a natural history account related to snake behavior (particularly vipers) in the ancient scientific literature. According to this story, when about to shed their skin, vipers eat the young offspring of fennel to recover a sharp sight.
However strange it might seem, the story has a scientific basis. At the moment of the shedding, the thin film of the snake’s eyes (the so-called caps) becomes milky/cloudy, blurring the vision of the snake. This is the so-called blue phase of the shedding process, which in fact announces the shedding. At that time, snakes might give the impression to be more aggressive than usual, whereas they are frustrated by a blurred vision. As soon as they shed the caps of the eyes, they recover their full sight and return to their normal behavior.
This shedding of snakes was known in the ancient scientific literature as early as the 2nd century BC through a rare piece of medico-scientific poetry from which later authors as the often-cited Pliny in the 1st century AD, for example, may have borrowed it.
The fennel-eating snake tale can be interpreted in different ways, as either an indication provided to humans by animal behavior on how to use plants for health purposes or, instead, as a projection onto the animal world of a human discovery as a way of explaining scientific discoveries. Either way, the ancient tale and the medical literature concord in their affirmation of the ophthalmological use of fennel to sharpen vision.
This ophthalmical use is confirmed and also precised by other ancient medical manuals, which also provide an indication about its possible origin. A medicine for the treatment of eye pathology can be found in the compendium compiled by the first-century CE Roman physician Scribonius Largus. This prescription appears again under his name in the vast manual of therapeutic by the Pergamon-born physician Galen (2nd/3rd cent. AD). There, however, it is listed in an enumeration of formulae coming from Egypt. The interesting point is that the way of using the medicine is explicited: according to Scribonius Largus, it is an eye wash, and, according to Galen, it treated leucoma.
In a particularly interesting continuity, in contemporary practice in the East (from China, India, and Pakistan through the Middle East) fennel still enters in medicines for the treatment of eyes, not only as a general way to improve eyesight, but also to successfully treat glaucoma.
Returning to the ancient tale, the explanation of the connection between snake’s shedding and the consumption of fennel might be simpler: at the time of shedding, that is, in the spring, fennel is sprouting, with tender, tasteful new shoots after the winter. Snakes would be right: fennel is delicately flavored, with a reminiscence of anise, and it is consumed as both as a spice (its foliage and seeds) and as a vegetable (its thick bulb).
In traditional Italian cuisine, its bulb is shaved to prepare wintery salads with oranges and black olives (or also walnuts and pomegranate), or to accompany fish, and it can also be braised as a vegetable to be served with a pork shoulder. In contemporary cuisine, its fronds may garnish a plate of meat or chicken to which they add a delicate taste, or they can be chopped and spread over a salad just as parsley or dill. Just as celery, fennel may be added to a soup, a broth, or a stew to increase their flavor.

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