This is an old article I touched up and re-released.  I hope you enjoy it!

Guizhi – Cinnamon twig – Emperor of Emperors 

In my opinion, there is no more important herb in the materia medica than Guizhi.  It is used in so many formulas, spanning all organ systems and the vastest number of pathologies of any herb (save, maybe, Gancao/licorice).  It is fortunately also still quite affordable, and not yet being considered for banning by the FDA.  :)

The plant

• Latin name/Pharmaceutical name: Cinnamomum cassia/Cinnamomi Ramulus
• Other common names: Cassia, Chinese Cinnamon.  Note well that the cinnamon we use in Chinese medicine is NOT the same species as normal, culinary cinnamon.  I think you could probably use culinary cinnamon in a Chinese herbal formula in a pinch, but it wouldn’t be the same.
• The growing plant: As I have never seen the growing plant, I’m going to have to outsource the physical description of the plant to someone better qualified – see Ms. Grieve on Cassia.  Looking at pictures, I am impressed by the plant’s stature (it is a tree, you know).  The leaves strike a dashing profile, with strong parallel veining and a robust texture.
• The dried herb: I’ve seen a few different forms – but the most common looks as if it is cut on a diagonal – it typically includes the bark even though some sources indicate all but the very thinnest bark should be removed.
• Bensky’s Materia Medica indicates that one should look for “young twigs without leaves or any withered parts.” From what I understand the thinner the twig, the better.
• Common preparations:Many different parts of the Cinnamon plant are used, including the bark (Rou Gui) and twigs with bark removed (Gui Zhi Mu). As far as preparation goes, I could only find common use of honey-fried Gui Zhi – the addition of heat and honey increases the warming capacity of Gui Zhi but impedes its ability to release the exterior. Bensky lists dry frying as another preparation but that does not seem to be widely employed.

Chinese medicine properties

Gui Zhi is listed in the category of herbs called “herbs that release the exterior.” The most common way of thinking about this category is by relating them to the Western concept of diaphoresis. However, herbs that release the exterior are capable of much more than just promoting a sweat. In contemporary literature, Gui Zhi is considered to be warm in nature and both sweet and pungent in nature. It is said to enter the Heart, Lung and Bladder channels. In the Shen Nong Ben Cao Jing, Gui Zhi is said only to be warm in nature and pungent in flavor – omitting the sweet flavor.

This is common, the adding of a flavor in contemporary understanding of an herb.  It is a helpful memory aid for students, but I’m not sure it actually adds anything to our understanding of the herb.

It is interesting to note how the doctrine of signatures works in evaluating this herb. Compared to another part of the Cinnamon tree – Rou Gui or Cinnamon Bark – Cinnamon twig is relatively superficial, light and outward spreading. Rou Gui is closer to the heart of the tree, more protective and heavier.

Historical-cultural information about Gui Zhi

Classical text descriptions: As already discussed above, the Shen Nong Ben Cao Jing (SNBCJ) describes Gui Zhi as being pungent in flavor and warm in nature. Another interesting thing in the SNBCJ – Gui Zhi is said to be good for counterflow Qi (vomiting, hiccough, etc) and situations where the Qi or breath are “bound up” and unable to move freely. Both of these are cases of fouled up movement – in the first, the movement is going in the wrong direction and in the second, the movement isn’t happening. This may relate to the pungency of Gui Zhi – it is capable of righting wrong movement and getting things moving that are stuck.

Etymology of the characters: Let’s look at the characters for Gui Zhi again – 桂枝. The left character, guì, refers to the tree itself and doesn’t seem to be particularly interesting. However, the right hand part of that character – the 圭 – is both the phonetic but is also used to refer to a kind of jade tablet used by rulers as a symbol of their power.

Medical applications of Gui Zhi

Common uses of Gui Zhi: This is one of the rare cases where TCM usage of the herb approximates what Classical texts indicate. Gui Zhi is often used in what TCM calls “deficient wind-cold attacks” which are, essentially, externally contracted illnesses (colds, flus) that involve sweating without provocation. Gui Zhi’s pungency and similar appearance to the energetic channels of the body also make it a prime candidate for use in unobstructing blocked channels as in Bi syndromes (bad pain in the body as one finds in arthritis and similar conditions).

There are several other uses ranging from rectifying Heart Yang deficiency (with attendant palpitations and shortness of breath) to warming and tonifying the center to rectify deficiency cold of the Middle Jiao (with attendant diarrhea and noisy bowels.)

Shang Han Lun: In the Shang Han Lun we find support for the TCM notion that Gui Zhi (in the formula Gui Zhi Tang) should be used in cases where a pathogen has invaded and the balance between Ying and Wei has been disturbed, producing sweat where there should be none. Where TCM calls this “deficient wind attack” the Shang Han puts it in the category of Tai Yang disease.

Other Classical Texts: I’ve talked a lot in the last year about the classical text called the Tang Ye Jing (汤液经).  In this mostly lost text, the five elements are used in a theory of “mutual containment” in this text. Regarding Gui Zhi, it is said to be the “wood herb of the wood class.” It exemplifies wood energy in its pungency – mimicking the outward spreading nature of living wood as we know it.

Related articles:

1. The qualities and uses of the Chinese herb Mahuang / 麻黃 / ephedra
2. An Exploration into Chinese herb flavor combinations – continued!
3. An exploration into Chinese herb flavor combinations – the final chapter