Hektoen International

A Journal of Medical Humanities

The doctrine of signatures

JMS Pearce
Hull, England

Fig 1. Doctrine of Signatures. Made Whole Nutrition.

Many of the ideas of scientists and physicians of the past have been proved false by subsequent advances in science. But some remain of interest in showing how our ancestors thought about diseases and how limited were their facilities to analyze and treat them. Up to the end of the sixteenth century, “resemblance” founded much of the knowledge and symbolism of Western culture.1 The words used to label various phenomena were related to resemblances. For instance, around 1541, the word “muscle” was used because of its resemblance to the Old English for mouse: mus, Latin mūsculus.

As long ago as AD 65, Dioscorides in ancient Rome noted that the herb scorpius resembled the tail of a scorpion, and might benefit those bitten by one. In the 1500s, Paracelsus von Hohenheim (1493–1541) in his book Dē rērum natūra developed the idea of the Doctrine of Signatures, believing that attributes of a plant such as shape, color, taste, and smell indicated its medicinal use. Based on resemblance, the Doctrine of Signatures gradually emerged and attempted to predict which foods, fruits, or herbal remedies (Fig 1) might relieve symptoms of illness.2

A few examples. The sori on the fronds of Asplenium scolopendrium—the Hart’s tongue fern—resembles the spleen, which caused the ancients to think it would be useful for treating ailments of the spleen. Similarly, lungwort (Pulmonaria officinalis), so named because its spotted leaves resemble lungs, was used for various pulmonary symptoms. The leaf of Hepatica acutiloba shaped like the liver was used to treat liver disorders. Heart’s ease (Viola tricolour) resembled the chambers of the heart and was therefore prescribed as a heart tonic and to ease the emotional pain of a broken heart. Paracelsus noticed that the Christmas rose (Helleborus niger) flowered in winter, and believing that it had revitalizing powers, he prescribed it to rejuvenate people aged over fifty.

The English botanist and herbalist William Coles (1626–1662) thought that walnuts (Juglans regia) were good for curing ailments of the head because “they Have the perfect Signatures of the Head: The Kernel hath the very figure of the Brain, and therefore it is very profitable for the Brain, and resists poysons…it comforts the brain and head mightily.”3 According to Coles, lily of the valley (Convallaria majalis) “cureth apoplexy by Signature; for as that disease is caused by a drooping of humours into the principal ventricles of the brain: so the flowers of this lily hanging on the plants as if they were drops, are of wonderful use herein.”

The Doctrine of Signatures started with the idea that God had marked everything he created with a sign (signature). The sign showed the divinely inspired clinical use. Following Paracelsus, the doctrine was promulgated by Jakob Böhme (1575–1624), a shoemaker in Görlitz, Germany who had profound mystical visions and wrote Signatura Rerum (The Signature of Things).4 His theosophist ideas were thought heretical, and for a few years he was silenced on threat of exile by the city fathers. Nonetheless, his concepts became influential and were applied to medical treatments. Culpeper’s famous Complete Herbal assumed along with astrology much of the doctrine, which also figured in many medical textbooks until the nineteenth century and persists today in homeopathic medicine.5

So, if you find the pockets or handbags of your headache clinic patients stuffed with walnuts or their shells, you will understand why. Mercifully for our patients, nowadays, physicians have no place for the application of this ancient but engaging story.


  1. Foucault M. The Order of Things: An Archaeology of the Human Sciences. New York, Pantheon Books, 1970.
  2. Pearce JMS. The Doctrine of Signatures. Eur Neurol 2008;60:51-2.
  3. Coles W. Adam in Eden, or, Natures paradise the history of plants, fruits. London, Streater 1657. cited in: https://quod.lib.umich.edu › eebo2
  4. Boehme J. The Signature of All Things (1621). Cambridge, Clarke, 1969.
  5. Dafni A, Aqil Khatib S, Benítez G. The Doctrine of Signatures in Israel-Revision and Spatiotemporal Patterns. Plants (Basel). 2021;10(7):1346.

JMS PEARCE is a retired neurologist and author with a particular interest in the history of medicine and science.

Spring 2024



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