Herb Name: Rou Gui (Cinnamon)
Alias: Jun Gui (Cinnamon Bark)
Harvesting and Processing: Collected mainly in autumn, dried in the shade.
Medicinal Part: Bark
Origin: Guangxi, Guangdong
Family: Lauraceae
Original Plant: Rou Gui (Cinnamon)
Plant Description: Evergreen tree.
Height: 12 to 17 meters. Bark is gray-brown, aromatic, and young branches are slightly quadrangular.
Leaves are alternate, leathery; long oval to nearly lanceolate, measuring 8 to 17 cm long and 3.5 to 6 cm wide, with a pointed tip and blunt base, entire margin, green and glossy above, gray-green and covered with fine hairs below; with 3 basal veins, prominently raised below, and fine veins running parallel.
Inflorescence is a cone-shaped cluster, axillary or near the apex, measuring 10 to 19 cm long, covered with short fine hairs; flowers are small, about 3 cm in diameter; pedicel is about 5 mm long; the flower tube is about 2 mm long, with 6 lobes, yellow-green, oval, about 3 mm long, densely covered with short fine hairs inside and outside; there are 9 developed stamens, in 3 whorls, anthers are oblong, 4-celled, lobed, with the outer 2 whorls having no glands, the 3rd whorl facing outward, with 2 glands at the base of the filaments, and 1 whorl of degenerated stamens inside; the pistil is slightly shorter than the stamens, with an oval ovary, 1-celled, with 1 ovule, the style is slender, nearly equal in length to the ovary, and the stigma is slightly disc-shaped. Flowering period is from May to July.
Berries are oval or obovate, slightly flattened at the tip, dark purple, measuring about 12 to 13 mm long, with persistent flower remains. Seeds are long oval, purple. Fruit ripens from February to March of the following year.
Rou Gui (Cinnamon) Characteristics: The product is in a tubular or rolled shape, measuring 30 to 40 cm long, 3 to 10 cm wide or in diameter, and 0.2 to 0.8 cm thick. The outer surface is gray-brown, slightly rough, with irregular fine wrinkles and transverse raised pores, some with gray-white spots; the inner surface is reddish-brown, slightly flat, with fine longitudinal lines, and shows oily marks when scratched. It is hard and brittle, easily broken, with an uneven fracture surface, the outer layer is brown and rough, while the inner layer is reddish-brown and oily, with a yellow-brown line between the two layers. It has a strong aroma, with a sweet and spicy taste.
Gui Tong (Official Cinnamon): Obtained from the bark of 5 to 6-year-old cultivated young trees or the bark of old tree branches, not pressed, naturally rolled into a tubular shape.
Qi Bian Gui (Edge Cinnamon): Obtained from the bark of trees older than 10 years, with both ends shaved to an angle, highlighting the cinnamon heart, placed between wooden uneven boards, pressed into a shallow groove shape with inward curling sides.
Ban Gui (Board Cinnamon): Obtained from the bark of the lowest part of old trees near the ground, placed in a wooden cinnamon press, dried until 90% dry, stacked and pressed for about 1 month until completely dry, becoming flat and board-like. Shows oily marks when scratched. It is hard and brittle, easily broken, with an uneven fracture surface, the outer layer is brown and rough, while the inner layer is reddish-brown and oily, with a yellow-brown line between the two layers.
The best quality cinnamon is characterized by being unbroken, heavy, with a thin outer skin, thick flesh, a purple fracture surface, high oil content, strong aroma, sweet and spicy taste, and minimal residue when chewed. The sweeter and spicier, the better.
Properties of Rou Gui:
【Shennong’s Classic of Materia Medica】 states: Jun Gui has a spicy and warm flavor. It is used for various diseases, nourishes the spirit, harmonizes colors, and is the foremost among all medicines. Long-term use leads to lightness and longevity, with a radiant complexion, maintaining youthful beauty.
It has a sweet and spicy taste, aromatic, and is warm in nature, entering the Jue Yin Liver Meridian (足厥阴肝经). It warms the liver and blood, breaks stagnation, dispels dampness and cold from the waist and legs, and alleviates abdominal and flank pain.
The liver belongs to wood and stores blood, with blood embodying wood’s energy, which is warm in nature. Warm energy rises to the left, yang harmonizes and spreads, accumulating to create heat, thus transforming into heart fire. The warmth of wood is half-rising yang, while the heat of fire is fully floating yang. People understand qi as yang, but do not realize it contains yin essence; they recognize blood as yin, but do not know it embraces yang energy. The warmth in blood is the source of transforming fire into heat; when warm energy is sufficient, yang is strong, and the person is healthy; when warm energy is weak, yin is strong, and the person is ill. When yang returns, life is restored; when yin prevails, death occurs. Life and death, beauty and ugliness differ; yang and yin, nobility and lowliness also differ. The movement of insects is known to all as life and death, but the lower classes do not understand the nobility of yin and the lowliness of yang, which has been the source of calamity throughout history.
To seek longevity, one must support yang energy. The method to support yang is to cultivate it within essence and blood, nurturing its root. When yang roots are weak, there is only deficiency in the water and wood, and there is no excess; there are no cases of excessive warm energy causing illness. The liver’s heat arises from insufficient essence, with warm energy being depressed, leading to wind dryness, not due to strong yang and weak yin.
Rou Gui warms and smooths, replenishing the warm energy in blood. The aromatic sweetness enters the earth, while the spicy sweetness enters wood; the spicy aroma is good at moving stagnation, thus it is best at resolving liver and gallbladder stagnation.
The flavor of metal is spicy, while the flavor of wood is sour; spicy and sour are the stagnation of metal and wood, leading to lung and liver diseases. The nature of metal is to gather, while the nature of wood is to disperse. Metal is said to follow the skin, thus it gathers, while wood is said to be straight, thus it disperses. Therefore, spicy leads to lung disease, while sour leads to liver disease due to stagnation. The lung benefits from sourness to gather, while the liver benefits from spiciness to disperse. When the lung receives sourness, it follows the descent, and the spicy flavor gathers; when the liver receives spiciness, it straightens and disperses the sour flavor. There are opposites that complement each other; this is one such case. The liver and spleen relax, warm energy rises and transforms into yang spirit, which governs, while yin evils have no power, thus the path to prolonging life is nothing but this.
All syndromes of meridian obstruction, organ blockages, joint stiffness, and abdominal pain are due to the decline of warm energy and coldness in the blood. This leads to upper and lower diarrhea, the nine orifices not being maintained, purple-black clots, and decay. Women’s menstrual and postpartum diseases all fall under this category. All should use Rou Gui, as other medicines cannot.
Rou Gui is the bark of the tree, also primarily acting on the exterior, but it is heavy and thick, thus it acts internally within the exterior. Its strength reaches the organs, differing from Gui Zhi (Cinnamon Twig), which primarily acts on the meridians. The bark is used.
【Origin】 Produced in Annam and regions such as Yunnan, Guangxi, and Guangdong, the tree is tall, and the bark is used in medicine.
【Properties and Taste】 Spicy and sweet, very hot, with slight toxicity.
【Indications】 Rou Gui is a key warming and tonifying medicine, primarily supporting fire and assisting yang, warming the interior and dispelling cold, capable of guiding fire back to the source, treating upper heat and lower cold, breaking through deep cold and stubborn cold, treating cholera and cramps, abdominal pain, hernia, and various pains in the heart and abdomen. 【Good Ancient Texts】 replenish the insufficiency of the life gate, benefiting fire and dispelling yin.
【Elements】 Replenishes the lower jiao insufficiency, treats deep cold and stubborn cold diseases, dispels wind-cold from the exterior, treats spontaneous sweating due to exterior deficiency, contraindicated in spring and summer, and for lower abdominal pain in autumn and winter. Without this, it cannot stop.
【Wang Ang】 Wood becomes dry with cinnamon, and it can also suppress liver wind and support spleen earth, treating spleen deficiency with poor appetite, excessive dampness, and diarrhea, tonifying labor and unblocking the meridians.
【Ling Tai】 Supports yang energy and expels yin evils.
【Dosage】 Generally 3 to 10 grams.
【Contraindications】 Avoid raw scallions, resin, and fire roasting; caution in cases of yin deficiency with internal heat, dry mouth, and thirst. For poisoning from wood fruits or melons, and from closed-mouth Sichuan pepper, using Rou Gui decoction can resolve. Rou Gui is generally used raw for stronger effects. It is said to have the fire of the earth, entering the blood, but Zhang Zhongjing used it for its qi transformation, not for blood transformation. Rou Gui guides heart fire down to interact with water, requiring Fu Zi (Aconite) to invigorate kidney yang to move its qi; this is the ability of Rou Gui to transform qi, hence the need for Fu Zi.
【Preparation】 Remove impurities, scrape off rough skin, and brush off dust to obtain.
Rou Gui is very spicy and very warm; although it has a metal flavor, it is essentially of wood and fire nature, thus it primarily enters the heart and liver blood, assisting the source of blood transformation. Cinnamon bark can also rise. Zhang Zhongjing’s Fu Mai Tang (Restore the Pulse Decoction) uses Gui Zhi (Cinnamon Twig) for its entry into the heart to assist fire and transform blood.
【Rong Chuan】 Rou Gui has a thicker flavor than Gui Zhi, with a more concentrated aroma. It is the ultimate of wood; very spicy leads to very warm, capable of benefiting heart fire, as it is a specialized medicine for generating fire from wood. In fact, it is a warming liver product. The liver is the mother of the heart; if it is deficient, it should be supplemented.
【Ni’s Note】 Generally, Gui Zhi is often used for arterial circulation issues, capable of promoting yang and reaching the exterior.
【Appendix】 Gui Xin (Cinnamon Heart) primarily supplements yang, invigorates blood, treats all wind diseases, replenishes five labors and seven injuries, opens the nine orifices, benefits joints, enhances vision, warms the waist and knees, breaks phlegm and stagnation, dispels blood stasis, treats wind bi and joint contraction, reconnects tendons and bones, and generates muscle.
【Ri Hua】 Treats nine types of heart pain, unbearable abdominal cold pain, cough with reversed qi, foot numbness, stops diarrhea, kills three worms, treats nasal polyps, breaks blood stasis, opens menstrual blockages, and retains the placenta.
【Zhen Quan】 Primarily guides blood to transform sweat and pus, internally expelling abscesses, treating obstruction and fullness in the abdomen.
【Preparation】 Remove impurities and rough skin. Crush before use.
【Properties and Taste】 Spicy, sweet, very hot.
【Meridian Entry】 Enters the Kidney, Spleen, Heart, and Liver Meridians.
【Functions and Indications】 Replenishes fire, assists yang, guides fire back to the source, disperses cold, stops pain, invigorates blood, and unblocks meridians. Used for impotence, cold in the uterus, cold pain in the waist and knees, kidney deficiency causing wheezing, yang deficiency dizziness, red eyes and sore throat, cold pain in the heart and abdomen, deficiency cold vomiting and diarrhea, cold hernia, and menstrual blockages.
【Dosage】 1 to 4.5 grams.
【Caution】 Use with caution in those with bleeding tendencies and pregnant women; not suitable for use with red resin.
【Storage】 Store in a cool, dry place, tightly sealed.