Both edible and medicinal plants were classified by their qualities in the Middle Ages. A given plant might be heating, cooling, moistening, or drying in its action on human bodies; the intensity of this action was expressed in degrees. An herb or foodstuff that was a little cooling was “cold in the first degree,” while a very cooling plant was classed as “cold in the fourth degree.” Above, left: Strawberry (Fragaria vesca) was a mildly cooling fruit, being cold and moist in the first degree. Pear (Pyrus communis) was more refreshing, being cold in the second degree and moist in the first.
The medicinal model inherited by the Middle Ages, based largely on humoral theory, was essentially a “cure by contraries” rooted in the idea that illness was the result of an imbalance of the humors—blood, choler, bile, and phlegm—within an individual. Plants and other substances were either warming, cooling, moistening, or drying in their action on human bodies, which were sanguine, phlegmatic, melancholic, or choleric in complexion. Both plants and bodies were composed of the four elements of fire, water, air, earth, and air and derived their qualities or temperaments from the particular combination of these elements. Theoretically, a physician could return a patient to health by administering food and drug plants whose action could restore the proper balance. A regimen would be prescribed based on the individual’s own temperament, age, and condition, as well as the time of year and his or her geographic location. For example, a condition caused by excessive heat and dryness, such as a skin eruption, could be soothed by a cold, moist substance.
The literary scholar E. M. W. Tillyard, whose The Elizabethan World Picture stresses the medieval character of many of the beliefs and attitudes current in sixteenth-century England, offers a particularly succinct and lucid account of the humoral theory which was inherited from antiquity and remained fundamental to medieval and early Renaissance medicine:
Man’s physical life begins with food, and food is made of the four elements. Food passes through the stomach to the liver . . . . The liver converts the food it receives into four liquid substances, the humours, which are to the human body what the elements are to the common matter of the earth. Each humour has its own counterpart among the elements. The correspondence is best set out in a table.
Element Humour Common Quality Earth Melancholy Cold and dry Water Phlegm Cold and moist Air Blood Hot and moist Fire Choler Hot and dry
In normal operation all the humours are carried together by the veins from the liver to the heart, a proper mixture of the humours being as necessary to bodily growth and functioning as that of the elements to the creation of permanent substances. The four humours created in the liver are the life-giving moisture of the body.
Salad plants were an important part of the medieval diet; while some greens were cultivated, still others were gathered from the wild. Above, left: The delicious garden sorrel (Rumex acetosa) was classified as both cold and dry in the second degree. The succulent purslane (Portulaca oleracea) was cold in the first degree and moist in the first.
The qualities assigned to medieval plants often seem to derive quite logically from their physical nature. Melons and cucumbers are cold and humid, and could be used to cool hot fevers and purify the urine. Squash, too, is cool and moist. According to the Tacuinum Sanitatis, squashes quench thirst and are good for people of choleric temperaments, and for young people; they ought to be eaten by everyone in the summer, especially in the south. While fresh figs are hot and moist, dried figs are hot and dry; hence they made a good winter food, especially for old people. (It was recommended that you drink cool water immediately after eating figs, to temper their natural heat.)
While we might concur with the qualities assigned above, we may be surprised at the qualities assigned to other herbs, such as mint, which was thought to be good for the stomach and to revive those who had fainted. We do think of mint as digestive and refreshing, but we also think of it as cool. To the medieval way of thinking, mint was hot and dry in action. However, the name “peppermint,” given to Mentha x piperita, does convey the idea of heat.
While we think of mint as cooling, the action of spearmint was classified as hot and dry in the third degree. The name “peppermint,” given to a spontaneous cross between spearmint (Mentha spicata) and watermint (Mentha aquatica), conveys the idea of heat.
A plant might be hot or cold, dry or moist in the first, second, third, or fourth degrees. The greater the imbalance, the greater the degree of action required. Within this system, most plants assigned to the fourth degree in medieval herbals are either toxic or very drastic in their effects. Poisonous mushrooms are moist and cold in the fourth degree, while opium is cold and dry in the fourth. As Frank Anderson notes in An Illustrated History of the Herbals, the concept of degrees was very well explicated by the great sixteenth-century herbalist William Turner:
A Degree is in Latin gradus, and it cometh of gradior, to go, and is named in Greek apostasis, that is a standing or a going away from. The cause of the name is this: There are certain herbs that are temperate, that is of a quality or property between hot or cold, and are neither notably hot nor cold. And if any herb depart from the temperate toward heat, and is sensibly felt a little hot, it is called hot in the first degree, and if it is a little hotter, it is called hot in the second degree, as though it had made two steps or departings from temperate. If an herb be very hot, it may be called hot in the third degree. If it be so hot as it can be, then it is called hot in the fourth degree, and so may ye understand the degrees of hot, cold, moist and dry herbs.
The attribution of disease to an imbalance of the humors is found in the writings of Hippocrates of Cos. Humoral theory was greatly developed and elaborated by Galen. For information on humoral theory in Arabic medicine, and its role in Persian medical culture, see “Humorism” in the Encyclopedia Iranica.
Anderson, Frank J. An Illustrated History of the Herbals. New York, Columbia University Press, 1977.
_____ ed. “Herbals through 1500,” The Illustrated Bartsch, Vol. 90. New York: Abaris, 1984.
Lewis, C.S. The Discarded Image: An Introduction to Medieval and Renaissance Literature. Cambridge: Cambridge University Press, 1964.
Siraisi, Nancy G. An Introduction to Medieval and Renaissance Medicine. Chicago, University of Chicago Press, 1990.
Tillyard, E. M. The Elizabethan World Picture. New York: Random House, 1961.
Tags: Fragaria vesca, Galen, Hippocrates, humors, Mentha x piperita, mint, pear, peppermint, Portulaca oleracea, purslane, Pyrus communis, Rumex acetosa, sorrel, strawberry, Tacuinum Sanitatis, Tillyard, William Turner