Doctrine of Signatures

For several centuries, herbalism was influenced by the Doctrine of Signatures. It was believed that plants were given a "signature" or a "mark" and their shape, colour, texture, habitat, and taste were a clue to the plant's healing properties.

Doctrine History

Although its beginning probably dates back into antiquity, the Doctrine was made popular during the European Renaissance by Paracelsus (Theophrastus Bombastus von Hohenheim, 1493-1541), a Swiss alchemist, physician, and astronomer who wrote about the Doctrine's virtues. He believed that plants tended to grow where they were most needed; for example, dock leaves useful in treating the sting from nettle grew near nettles.

Jacob Boehme (1575-1624) of Georlitz, Germany was also credited for invigorating the Doctrine's popularity when he wrote the first published book pertaining to the topic called Signatura Rerum, "The Signature of All Things." The book had a strong religious/spiritual base and eventually became widely accepted and valued for its medical contribution.

Some of the known signatures of that time included lungwort, a flowering plant with spotted leaves that resembled a diseased lung, believed to be important for pulmonary problems. The redness in beets would fortify the blood. Walnuts, resembling the brain, were believed to be important for the brain, kidney beans for the kidneys. Ginseng root, resembling the male anatomy, was good for sexual vitality.

The Doctrine Today

Hundreds of years later, there are studies supporting earlier observations of these herbalists. Lungwort is an expectorant helping to remove catarrh from the lungs; walnuts with their high omega-3 oil content are considered a "brain food;" kidney beans assist the kidneys by removing excess phosphorus. How early herbalists were able to obtain specific information by observing the plants is difficult to know for certain, but it is clear that the benefits of these plants are just as relevant today as they were then.

The Doctrine and China

The Chinese extend the Doctrine whereby the colour and taste of a food is a reflection of its medicinal importance. It is believed that yellow and sweet foods relate to the spleen; red and bitter foods relate to the heart; green and sour foods relate to the liver; and black and salty foods relate to the lungs. Herbs were also categorized as hot, dry, cold, or damp still an important aspect of herbal healing in different parts of the world.

The Doctrine and Islam

Islamic herbalists believed that plants growing above the ground were appropriate for ailments of the upper body and plants that grew below the ground were appropriate for ailments of the lower body. Ginger, being a root plant, was appropriate for illnesses of the lower body, such as indigestion. Aloe vera, which grows above the ground, was used to treat headaches and mouth sores.

Today it may not be seen as very practical, or even safe, to treat ailments by picking flowers and plants only based upon their appearance, shape, taste, or habitat, but taking a closer, informed look at the plants and flowers growing around us can be a very rewarding experience. Through careful observation you will be able to see the plants' growing preferences, likes and dislikes, strengths and weaknesses, and you may even find that sometimes you can judge a book by its cover.