An important concept in most schools of herbalism is that of the doctrine of signatures. The doctrine of signatures states that the herbs will, in some way, physically resemble their realm of therapeutic action. The resemblance may be obvious or hidden, but searching for it and seeking to understand it can help us in our quest to understand how herbs impact the human body.
In some way, the same universal forces that acted to shape the human body, disease processes that impact it, and the forces of healing that rectify imbalance are all also acting on the plants and other materials that make up the herbal materia medica. Everything is connected and exerting influence on everything else.
The most basic level of the doctrine of signatures pertains to the color, shape/texture or habitat/behavior of the herb in question. These properties in one way or another point to its healing characteristics. I’ll briefly explore a couple of the more obvious properties through some examples from Chinese herbalism.
Color as Herbal “Signature”
Qingpi 青皮 – Immature Bitter Orange Peel
Qingpi can be translated simply to “blue-green peel,” so this herb has a double dose of symbolic relevance! Although the dried herb doesn’t have much of a green tinge, the unripe fruit is greenish. This green color (and the “green” quality of immaturity) strongly resonates with the color of the wood phase element and thus the Liver and Gallbladder organ systems.
In most of the standard herbal texts, you’ll learn that one of this herb’s primary functions is to move stagnant Liver qi, alleviating abdominal discomfort that is oriented around the ribsides and upper abdomen. Other citrus species we use in Chinese herbalism, such as Zhishi, impact the abdomen and are also qi movers, but have less of a Liver orientation and are instead focused more on the Stomach and Large Intestine.
Xuanshen 玄參 – Scrophularia root
This is another herb with a color in it’s name – Xuan is one word for black, but can also mean dark, mysterious or profound. Scrophularia root is dark in color and the best quality is quite black. This color resonates with the water phase element, and the Bladder and Kidney organ systems especially. While most people think of the direct action of clearing heat in the case of heat related pathogens, the focus of the herb is actually on tonification of the yin. Through strengthening the cold water of the North, this bitter cool herb extinguishes excessive fire related symptoms like angry skin eruptions and even insomnia.
Shape/Texture as Herbal “Signature”
Lianqiao 連翹 – Forsythia fruit
In this case, the shape of the herb relates it to the part of the body it works on. Lianqiao looks like a chambered heart when the fruit is split in half – which is how our decoction pieces are typically delivered. This heart shaped resonance seems to indicate the treatment of disorders of that organ system.
Indeed, this herb is in the category of herbs that clear heat – a common pathogen of the Heart organ system – and is especially good at clearing Heart/upper burner heat which might result in fever, insomnia and difficulty thinking.
Gou Teng 鉤藤 Gambir vine
You only have to look at Gou Teng once to be impressed by it. The hook shape can be thought of as useful in “hooking” something gone astray. In this particular case, the hooking is done on what TCM refers to as “Liver wind rising,” which can cause tremors and seizures.
Habitat & Behavior as “Signature”
Fuling 茯苓 – Poria
This herb is a fungus that grows around the roots of Chinese red pine. This tree is known as a symbol of longevity and strength, and it is often depicted in Chinese art as a central figure, often cliffside or in a similarly challenging position. The strength to endure in difficult circumstances can be associated with Spleen or Kidney. It is a food item, and similar species are used around the world as food sources. This associates it with the Spleen and Stomach.
As a fungus, an an underground one at that, it is an expert in dealing with moisture. When heavy rains come through, it must allow the fluids to pass through as needed, without disturbing the structure that holds the tree in place. When there are periods of less moisture, the fungus must conserve its fluids, which of course has some benefit for the tree as well. This mutually beneficial relationship, and great facility with fluids continues to associate this powerful and ubiquitous herb with the Spleen.
And of course, if we look at the clinical manuals of Chinese herbalism we see the strong association that Fuling has with treating fluid metabolism disorders and strengthening the Earth organ systems. It can treat mental emotional disturbances like insomnia and anxiety as well, through reducing the pressure of water on fire, and strengthening the centering power of Earth. A very important herb for practicing in wet, cold Oregon!
Bie Jia 鱉甲 – Soft shelled turtle shell
This animal dives into water, but perhaps more importantly, is known for burying itself in the sand. These two behaviors resonate it deeply with the Yin. One of its primary actions is to nourish the Yin. I believe it is also a snapping turtle, and this would help to explain its effect of invigorating the blood and breaking up clumps and nodules.
Are the Chinese herbal properties of flavor and nature also based on the doctrine of signatures?
On some level, the wei and qi of herbs is an aspect of the doctrine of signatures, albeit on a more subtle level. The quality of pungency, for instance is a flavor that reminds us of outward movement, agitating motion and an opening quality. Pungency of herbs does all of these things and the most pungent herbs resonate deeply with these properties. So, although not all Chinese herbs bear obvious physical manifestations as in some of the examples above, they all have properties that resonate with the impact that they have.
Are we discovering or inventing?
I’ve sometimes had problems taking the doctrine of signatures seriously. One reason is it’s lack of consistency. There is a diverse range of meanings the doctrine of signatures is given – the herb can resemble (closely or simply symbolically) the part of the body effected by the disease process, it can resemble the disease itself or it can resonate with the healing process in the body impacted by the condition in question. Additionally, if some herbs work within the more obvious and explicit doctrine of signatures theory (color, shape, behavior – not Chinese properties) – why not all of them?
However, even if it is just a convenient human construction – it’s a great deal for students of herbal medicine. I remember herbs so much better with which I have established a strong mnemonic based on the doctrine of signatures! When I learn a new herb, I work hard to find a way that the doctrine of signatures fits.
I’d be very interested to hear about your understanding of the Doctrine of signatures and any fun examples you have of herbs that are easy to explain using this theory. The comments on this article are open!
[This post has been updated during the 2020 site updates. My goal during post updates was to keep the character of the original post, but update for corrections and clarity, as well as to remove broken links.]