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Cassia Bark is the dried bark of the Cinnamomum cassia and Cinnamomum cassia var. macrophyllum plants of the Lauraceae family. It is either wild or cultivated, primarily produced in Guangxi, Guangdong, Yunnan, and other regions. The original plant Cinnamomum cassia thrives in tropical and subtropical climates with high temperatures, no frost or snow, and foggy, humid conditions. It has weak cold resistance and grows best in deep, loose, well-drained acidic soil. Cinnamomum cassia var. macrophyllum prefers warm and humid climates, has strong adaptability to temperature, and grows best in deep, loose, well-drained acidic red or yellow soil. It has a pungent and sweet taste, and is extremely hot in nature. It belongs to the kidney, spleen, heart, and liver meridians. Its effects include tonifying fire and assisting yang, guiding fire back to its source, dispersing cold and unblocking meridians, dredging collaterals, and relieving pain. The clinical name is Cassia Bark.

bubble_chart Compendium of Materia Medica

Yaoxing Lun: Monarch, tastes sweet and pungent. Can relieve cold wind and pain.

Rihuazi Bencao: Treats all wind qi, supplements five strains and seven injuries, unblocks nine orifices, benefits joints, enhances essence, improves vision, warms the waist and knees, breaks abdominal masses and accumulations, disperses static blood, treats migratory impediment, joint contractures, strengthens tendons and bones, and promotes muscle growth.

Kaibao Bencao: Tastes sweet and pungent, extremely hot, and toxic. Mainly warms the middle, benefits liver and lung qi, treats cold and heat in the heart and abdomen, cold diseases, cholera, muscle cramps, headache, lumbago, promotes sweating, relieves irritability, stops saliva, cough, and nasal congestion, can cause early abortion, strengthens joints, unblocks blood vessels, regulates deficiencies, and guides all medicines without fear.

Yaolei Faxiang: Supplements the deficiency of lower energizer ministerial fire. Treats deep-seated cold and chronic cold diseases, as well as exterior deficiency spontaneous sweating. It is a prohibited medicine during spring and summer.

Yaoxing Fu: Tastes pungent, hot, and toxic. It is floating, yang within yang. The thin qi is Cinnamon Twig; the thick qi is Cassia Bark. Thin qi disperses, Cinnamon Twig ascends and releases the exterior; thick qi causes fever, Cassia Bark descends and supplements the kidney—this is the way of heaven and earth, favoring the upper and favoring purgation.

Tangye Bencao: Qi is warm, tastes sweet and pungent, slightly toxic.

Enters the hand Shaoyin meridian. Cinnamon Twig enters the foot Taiyang meridian.

The "Materia Medica" states: It primarily warms the middle, benefits liver and lung qi, treats cold and heat disorders of the heart and abdomen, cholera muscle cramps, headache and lumbago, promotes sweating, relieves irritability and stops salivation, cough, and nasal congestion. It can induce early abortion, strengthen joints, promote blood circulation, and address deficiencies in the body's regulatory functions. It is suitable for guiding all medicines and is fearless. The "Yanyi" claims that cinnamon is extremely hot. The "Suwen" states that it is pungent and sweet with a dispersing effect, pertaining to yang. Therefore, Zhang Zhongjing's Cinnamon Twig Decoction for treating cold-damage disease with exterior deficiency requires this herb, emphasizing the use of pungent and sweet properties. It also states: Treat cold with heat. Thus, it is understood that among the three types of cinnamon, the fungus cinnamon and male cinnamon are not chosen because these two types are only warm and cannot treat wind-cold diseases. Only the powder on a quarter of a coin cinnamon, as stated in the "Benjing" , is sweet, pungent, and extremely hot, perfectly aligning with the "Suwen" theory of pungent and sweet with dispersing effect pertaining to yang, further confirming the deficiency of fungus cinnamon and male cinnamon. However, the "Benjing" only mentions cinnamon, while Zhang Zhongjing also refers to Cinnamon Twig, likely referring to the bark of the twig. The thick part of the trunk is not useful. Various scholars' opinions are merely their own views without evidence. Now it is also called official cinnamon, but the origin of this name is unknown, and it is feared that future generations might consider it a different substance, hence it is recorded here. There is also Cassia Central Bark, which is the core of various cinnamons, but it is not as effective as the powder on a quarter of a coin cinnamon. The "Bieshuo" mentions that what merchants from Jiaoguang trade and what doctors use, only Chen Cangqi's explanation is the most accurate. However, the thick and heavy-smelling fungus cinnamon is suitable for treating internal organs and lower energizer medicines. The lighter ones are suitable for eye treatments and dispersing medicines. The "Benjing" uses fungus cinnamon to nourish the spirit and male cinnamon to benefit the joints. Zhang Zhongjing uses Cinnamon Twig for inducing sweating in cold-damage disease. Cinnamon Twig refers to the twigs of cinnamon, not the trunk, chosen for their lightness and ability to disperse. A type called Willow Cinnamon, which are small tender twigs, is especially suitable for upper energizer medicines. Zhang Zhongjing's decoction uses Cinnamon Twig to induce sweating and Cassia Bark to tonify the kidneys. What originates from heaven is close to the upper, and what originates from earth is close to the lower, a natural principle that cannot be altered. Any deviation will significantly affect efficacy. Over time, habits become flaws, leading to the deficiency of ancient knowledge in later generations. Cassia Central Bark has mystical effects that cannot be fully described, and the various types of cinnamon differ in size and maturity. Observation is key. The "Materia Medica" mentions it has minor toxicity, which transforms according to its category. When used with Skullcap Root and Coptis Rhizome, the minor toxicity is neutralized. When used with Aconite and Prepared Aconite, it fully acquires their hot nature; if used with toxic substances, the minor toxicity is removed, but the major toxicity increases; when used with Ginseng, Ophiopogon Tuber, and Liquorice Root, it can regulate the middle and tonify qi, making it suitable for long-term use. This herb can protect the nutritive qi and strengthen the defensive qi, acting on the Foot Taiyang meridian. Cassia Central Bark enters the heart, acting on the Hand Shaoyin meridian. If referring to the nutritive aspect, it is a blood medicine, hence the "Classic" mentions promoting blood circulation. When used with Croton Fruit, Sal Ammoniac, Dried Lacquer, Pangolin Scales, leech, and gadfly, which are toxic, the minor toxicity transforms into major toxicity, demonstrating its transformative nature. The decoction uses Cinnamon Twig for inducing sweating and Cassia Bark for tonifying the kidneys. Why does the Minor Bupleurum only mention adding cinnamon? The "Yao Xiang" states that Cassia Bark is extremely pungent, tonifies the lower energizer's heat and fire deficiency, treats deep-seated cold and chronic cold, and treats exterior deficiency with spontaneous sweating. It is contraindicated in spring and summer.

Zhenzhunang：In autumn and winter, treat lower abdominal pain, only cinnamon can stop it.

Yongyao Xinfa：Cinnamon Twig is light in both qi and flavor, thus it can ascend and disperse to the surface. For internal cold, use Cassia Bark; for tonifying yang, use Willow Cinnamon. Cinnamon, pungent and hot, disperses cold in the meridians and guides yang qi. If healthy qi is deficient, use pungent to moisten it. It disperses cold evil and treats running-piglet.

Bencao Yanyi Buyi ：Deficiency can be supplemented, this is the great principle. Zhongjing uses Cinnamon Twig to rescue the exterior, not because the exterior is deficient and needs to be supplemented by cinnamon. The defensive qi has wind-cold, hence the disease of spontaneous sweating. Cinnamon Twig disperses the evil, and when the defensive qi is harmonized, the exterior becomes firm, and sweating stops by itself. It is not that Cinnamon Twig can stop sweating and treat it. Now, 《衍義》 says that Zhongjing treats exterior deficiency, which is wrong! 《materia medica》 only mentions sweating, which is exactly Neijing the meaning of pungent and sweet dispersing. Later generations using cinnamon to stop sweating have lost the essence of the classics. The so-called official cinnamon is the highest quality cinnamon, which can be used fully and is named as a term of honor. The so-called Cassia Central Bark is the thick meat of the bark, removing the thick and tasteless part, leaving only the layer near the wood that is pungent and sweet, hence called the heart, a term of praise, why doubt it. Cinnamon is known in three types, not including Cassia and Cassia Bark, because these two are only warm in nature and cannot treat wind-cold diseases. Only the powder on quarter of a coin cinnamon, as mentioned in the classics, is pungent, sweet, and very hot, exactly matching Suwen the theory of pungent and sweet with dispersing effect pertaining to yang. Also, another theory says: use Cassia to nourish the spirit, use Cassia Bark to benefit the joints. There is also a type of Willow Cinnamon, which is the small tender branches of cinnamon, especially suitable for use in upper energizer medicines.

Bencao Gangmu ：agonizing arthralgia, wind aphonia, yin exuberance and blood loss, diarrhea and fright epilepsy.

《materia medica 乘雅》：Cassia Bark is purple-red, has flowers but no seeds, obtaining the beginning of yang; Cassia is green-yellow, has flowers and seeds, obtaining the beginning of yin. Cassia Bark is male, Cassia is female. The wonderful use of cinnamon, to promote and report, all in harmony. Cassia Bark dominant qi causes pharyngitis, mental activity is blocked, joints are not beneficial, these are diseases that need to be promoted. Cassia Bark first promotes and captures middle qi, and then promotes. It also treats upper qi cough, inability to inhale, instead spitting out the inhalation, these are diseases that need to be captured. Cassia Bark first promotes and hires a messenger, this is the yin qi of the zang that needs to be promoted. Cassia first promotes and captures the spirit, and then promotes. If promoting without first capturing, capturing without first promoting, this is disharmony, this is discord. Cassia promotes and captures the five zang yin spirit zang; Cassia Bark promotes and captures the four middle qi joint orifices and vessel form zang. The differences in efficacy are due to the differences between male and female. Not only are there differences, but each also divides into clans, hence each follows its own clan to have differences in upper and lower, internal and external, light and heavy, thick and thin. The flavor is pungent and warm, the efficacy is equal to fire, treating with cold as the root, yin as the branch, and cold water as the transformation; or the root's original qi seems hidden, and the branch's cold transformation is instead apparent; or yin qi carries yang, and blood runs wild; or water cold is excessively harmful, and cold extremities pour out; or fire does not return to the source and external flames internal cold; or fire loses its tip and becomes blind, deaf, mute; or true fire extinguishes and pathogenic fire blazes; or strong fire is abundant and small fire is extinguished, externally showing cold and sour, should be taken as food. As for driving wind, it is as fast as shadow and echo, with the Kshatriya species.

《medicinal property 解》：Cinnamon, pungent and sweet in flavor, very hot in nature, toxic. The thickest at the bottom is called Cassia Bark, removing the rough skin to become Cassia Central Bark, enters the heart, spleen, lung, and kidney meridians, treats nine types of heart pain, supplements labor injury, opens the nine orifices, warms the water zang, continues the bones and tendons, kills three worms, disperses qi stagnation, breaks blood stasis, expels the placenta, eliminates cough, treats abdominal pain, stops diarrhea, and is good at inducing sweating. The next thickest in the middle is called official cinnamon, enters the liver and spleen meridians, treats middle energizer deficiency cold, accumulation and pain. The thinnest at the top is called thin cinnamon, enters the lung and stomach meridians, treats upper energizer cold, moves the shoulders and arms and travels the limbs and joints. The tender branches that sprout are called Cinnamon Twig, specifically enters the lung meridian, treats releasing the flesh and effusing the external, regulates cold-damage disease with sweating. All four can kill plant and wood toxins, and are fearless of any medicine. It is contraindicated with scallions.

Note: Cassia Bark, being below, has the principle of entering the kidneys; it belongs to fire and has the fire that enters the heart; its pungent dispersing nature aligns with the lungs, and its sweet warm nature pleases the spleen, hence it enters both. Official Cinnamon is in the middle, and both the liver and spleen are middle organs. Moreover, the classics say: the liver desires to disperse, urgently consume pungent to disperse it, and use pungent to supplement it; it also says: the spleen desires to be relaxed, urgently consume sweet to restore it, and use sweet to supplement it. The taste of cinnamon is pungent and sweet, which is why it enters these two meridians. Thin Cinnamon is above, and since the lungs and stomach also reside above, it is suitable to enter them. Cinnamon Twig, being four dispersions, has the meaning of dispersing, and both its qi and flavor are light, suitable for entering the Taiyin and governing the exterior. Danxi said: Zhongjing used Cinnamon Twig to rescue the exterior, not because the exterior was deficient and used it to supplement. The defensive qi has wind-cold, hence the disease of spontaneous sweating, using this to expel the pathogen, then the defensive qi harmonizes and the exterior becomes dense, and the sweating stops by itself. The "Yanyi" mistakenly said that Zhongjing treated exterior deficiency. The "Materia Medica" says that cinnamon induces sweating, which exactly matches Suwen the meaning of pungent and sweet dispersing. Later generations used cinnamon to stop sweating, losing the meaning of the classics. Generally, cinnamon is yang within yang, and those with vigorous fire in their prime should avoid it, only those with declining fire at the life gate unable to generate earth, with undigested food and postpartum weakness should use it.

Yaojian: Pungent in taste, hot in nature, toxic, with a thin odor and floating property, it is yang within yin. There are generally four grades. The thickest at the bottom is called Cassia Bark. Removing the rough bark and retaining the part near the wood, which has a thick and most refined taste, is called Cassia Central Bark. Adding two to three parts to a yin tonic can help alleviate stagnation caused by Rehmannia and tonify the kidneys. Due to its pungent taste, which belongs to the lung, it can generate kidney water. Its warm nature promotes blood circulation and can dissolve stagnation, thus it is certain to tonify the kidneys. The medium thickness in the middle is called Official Cassia, mainly used for cold in the middle energizer. The thinner part at the top is used for moving the shoulders and arms and relieving stagnation in the limbs, often used as a guiding herb for the shoulders and arms. The thinnest part from the young branches is called Cinnamon Twig, suitable for cold-damage disease and common cold with sweating, to slightly relieve the exterior, not to consolidate the exterior. Only for those with sweating, where the exterior deficiency and evil are slight, this thin, pungent, and sweet agent is used to gently disperse, thus stopping sweating. How can a pungent and sweet agent consolidate the exterior? In small amounts of one to two parts, thin cassia can assist in activating blood circulation in pox treatments, promoting smooth blood flow and pox clearance. It can also treat cold-induced abdominal pain. However, it is strictly contraindicated for those with hot bodies and reckless blood flow. Avoid using with gypsum and pregnant women.

Jingyue Quanshu: Pungent and sweet in taste, very hot in nature, yang within yang. Slightly toxic, only the sweet-tasting ones are usable. Cassia is hot in nature, good at assisting yang, especially entering the blood aspect. For cold diseases in the limbs, nothing else can reach as effectively. Cinnamon Twig is light in qi, thus able to move to the exterior, good at regulating nutrient-defense, thus treating cold-damage disease, inducing evil sweat, treating common cold, and stopping yin sweat. Cassia Bark is heavy in taste, thus able to warm and tonify the life gate, strengthen bones and tendons, promote blood circulation, treat cold in the heart and abdomen, headache, cough, nasal congestion, cholera muscle cramps, pain in the waist, feet, navel, and abdomen, and all chronic cold diseases. Moreover, cassia is the king among woods, thus good at pacifying the yin pathogen of liver wood, and also good at assisting the yang qi of the liver and gallbladder. Because of its sweet taste, it is most beneficial for the spleen earth. For liver evil overcoming earth without fire, using this is extremely effective. Used with ginseng, aconite, and Rehmannia, it best reduces deficient fire and treats lower yuan yang deficiency. Used with Chinese Angelica and Sichuan Lovage Rhizome, it best treats postpartum blood stasis, abdominal pain from the child's pillow, and infantile smallpox with deficient cold, itching without rising. Although it is good at causing early abortion and moving blood, caution is needed for these two conditions. For lower energizer deficient cold, when the method is to return fire to its origin, this is an essential medicine, not to be mistakenly adhered to.

Bencao Beiyao: Very drying, tonifies the kidney and life gate fire.

Pungent and sweet, very hot, thick qi, pure yang. Enters the liver and kidney blood aspect, pacifies the liver and tonifies the kidneys. Tonifies the insufficiency of the life gate ministerial fire. Between the two kidneys, the ancestral qi of the prenatal, which is the true fire. Without this fire, life cannot exist; without the true yang fire, there is no way to steam the dregs and transform the essence, leading to spleen and stomach decline, qi exhaustion, and death. Benefits yang and eliminates yin, treats chronic cold and deep cold. Can induce sweating, promote blood circulation, and guide all medicines. Pungent is good at dispersing, hot is good at moving. Removes nutrient-defense wind-cold, exterior deficiency spontaneous sweating, yang deficiency. Cold pain in the abdomen, cough, and qi stagnation. Cough is also due to qi not returning to the origin, cassia can lead fire back to the dantian. Wood withers with cassia; carving cassia and nailing it into the root of a tree will kill the tree. Also suppresses liver wind and supports spleen earth. Excessive liver wood overcomes earth; pungent disperses liver wind, sweet benefits spleen earth. Treats red and swollen painful eyes with heat attacking heat, called following treatment. And spleen deficiency with aversion to food, life gate fire insufficiency. Dampness with diarrhea, earth overcome by wood, unable to control water. Ancient water-moving formulas also often used cassia, such as Five Ingredients with Poria Powder, Kidney-Nourishing Pill, etc. Tonifies labor, improves vision, promotes menstruation, causes early abortion. Pungent and hot can move blood, hence the caution. Works well with Ginseng, Liquorice Root, Ophiopogon Tuber. Avoid with raw onions and gypsum.

Benjing Fengyuan: Cassia Bark is pungent and hot, descending in nature, entering the foot Taiyin and Shaoyin meridians, connecting the Yin Heel and Governor Vessels. It has a strong aroma and taste, replenishing fire to disperse yin, greatly tonifying yang qi, and is suitable for those with insufficient lower energizer fire. Its nature is descending, guiding the source of fire. It is said that the kidney suffers from dryness, and it is urgent to consume pungent substances to moisten it, benefiting the liver and kidney, stopping cold pain in the waist and abdomen, cold phlegm, cholera, and muscle cramps, strengthening tendons and bones, and promoting blood circulation. Elements state that it supplements the insufficiency of the lower energizer, and for diseases of deep-seated cold and stubborn coldness, lower abdominal pain, it is indispensable. Shizhen used it to treat agonizing arthralgia due to wind-dampness, yin exuberance with blood loss, diarrhea, dysentery, fright epilepsy, all utilizing its pungent and warm properties to disperse stagnation. Ancient formulas treated children's fright epilepsy and diarrhea diseases, recommending Five Ingredients with Poria Powder to purge the fire of Bing and drain dampness from the earth. It contains Cassia Bark to suppress liver wind and support spleen earth, guiding water-draining herbs into the bladder. For red, swollen, and painful eyes, spleen deficiency leading to inability to eat, strong liver pulse, and weak spleen pulse, using cold herbs to treat the liver would further weaken the spleen; using warm herbs to aid the spleen would further strengthen the liver. However, doubling the amount of Cassia Bark in warm spleen herbs can kill liver and benefit spleen, achieving two effects with one treatment. Combined with Clove, it treats smallpox with gray collapse, as it can warm and promote suppuration. Moreover, Cassia Bark's pungent dispersing nature can open the uterus, breaking blood stasis to regulate menstruation, dissolve abdominal masses, break blood stasis for early abortion, internally support yin ulcers and long-unhealed abscesses, and for virtual yang ascending, causing a flushed face and hematemesis with nosebleeds, and a faint, large, and weak pulse, it is indispensable. For fetal restlessness due to cold purgation and descent, taking Skullcap Root and White Atractylodes Rhizome without response, with increasing pain and descent in the lower abdomen, and a string-like thin or floating and leathery pulse, only ginseng, astragalus, Cassia Bark, aconite, and the Ten Complete Great Tonics can warm and be effective. In the past, it was also said that those with blood deficiency should not use Cassia Bark. Shizhen used it to treat yin exuberance with blood loss, a principle not understood without a profound grasp of yin-yang theory. However, it is strictly contraindicated for yin deficiency with blood loss and a string-like, thin, and rapid pulse. Nowadays, it is ground into powder with lime in equal parts, applied on black plaster, and used to stick on stubborn lumps, also utilizing its pungent and warm properties to disperse stagnation. However, it is only suitable for those with coarse and thick skin.

Bencao Chongyuan: The cassia tree does not wither in winter, its scent is pungent and warm, its color is purple-red, and it is the wood fire born in water. For those with upper qi cough, if the lungs and kidneys do not communicate, then upper qi results in cough symptoms. Cassia initiates the yang of life in water, ascending to the lungs, thus calming upper qi and eliminating cough. For those with qi stagnation pharyngitis, if the triple energizer's qi does not circulate through the muscles, then qi stagnation results in pharyngitis symptoms. Cassia, embodying the wood qi of Shaoyang, facilitates the triple energizer, thus relieving qi stagnation and treating pharyngitis. For those with spitting and inhaling, if exhalation does not return to the root, it is expelled. Cassia can guide lowering qi to connect with upper qi, so that the inhaled qi reaches the dantian before being expelled, thus treating spitting and inhaling. The joints, including the two elbows, two armpits, two thighs, and two knees, are all chambers of the body's mechanisms. The 365 joints throughout the body are all places where the spirit qi travels. Cassia assists the monarch fire's qi, enabling the heart's spirit to move in and out of the mechanisms and travel through the joints, thus benefiting the joints. For tonifying the middle and replenishing qi, it supplements the middle energizer and benefits the upper purgation qi.

Bencao Qiuzhen: [Comment] Tonifies life gate fire, eliminates blood aspect cold stagnation.

Cassia Bark specifically enters the life gate and liver. Its scent is purely yang, pungent and sweet, very hot, directly penetrating the liver and kidney blood aspect, greatly tonifying the life gate ministerial fire. Ministerial fire is the true fire within the two kidneys, the ancestral qi of the innate. Without this fire, life cannot exist, hence when food and water enter the stomach, it is all here for digestion. Benefits yang and treats yin. Zhao Yang-kui said: To benefit the source of fire, to eliminate yin nebula, the Eight-Ingredient Rehmannia Pill is used. For all deep-seated cold and stubborn cold, nutrient-defense wind-cold, yang deficiency spontaneous sweating, cold pain in the abdomen, cough and qi stagnation, spleen deficiency and aversion to food, warm and excessive diarrhea, Li Shizhen treated agonizing arthralgia wind-dampness, yin exuberance and blood loss, diarrhea and fright epilepsy, all using the pungent and warm dispersing and resolving power. Ancient formulas for treating children's fright epilepsy and diarrhea diseases, the Five Ingredients with Poria Powder is used to purge Bing fire, drain earth dampness, containing cassia, to suppress liver wind and support spleen earth, guiding water-draining medicine into the bladder. For blocked blood vessels, retention of dead fetus, Cassia Bark's pungent dispersing ability can unblock the uterus and break blood stasis to regulate menstruation. For red, swollen, and painful eyes due to cold and stagnation, using this treatment is always effective. Because its scent is sweet and pungent, its color purple-red, it has the ability to invigorate blood and qi. Its nature is purely yang, with the power to conduct and induce movement. The ancients said this body qi is light and uplifting, capable of drastic tonification of the life gate, and also able to ascend and reach the surface to connect nutrient-defense. Truly. Unlike Aconite Lateral Root, whose scent is pungent but also slightly bitter, ascending and descending, only solidifying true yang, without also entering the acquired uses. Therefore, for patients with cold descent, it is suitable for warming the middle, and for those with disharmony of qi and blood, desiring invigoration, smallpox not rising must use it. Then it is not necessary to use Aconite Lateral Root, only to drastically tonify the blood and qi within, adding Cassia Bark as an adjuvant, such as in the Ten Complete Great Tonification, Ginseng Nourishing Camp formulas, this is the meaning. Nowadays, people do not carefully understand, merely considering Aconite and Cassia both as pungent and warm, arbitrarily and recklessly administering, not carefully distinguishing, is this the way for those who should be discerning medicine for health and saving the root? But for those with essence depletion and blood deficiency, liver excess and fire rising, it is strictly contraindicated.

Depei Bencao: Fears raw scallions and stone fat.

Sweet, pungent, hot, slightly toxic. Enters the foot Shaoyin meridian, also enters the foot Jueyin meridian blood aspect. Tonifies the life gate's ministerial fire. Unblocks upper purgation yin constipation. Raises yang qi to connect with the middle energizer, opens all orifices and expels yin turbidity. From Shaoyang, it draws qi back to the liver, pacifies liver evil and supports spleen earth. All diseases caused by deficiency cold should be treated with it. Specifically warms the interior of the nutrient aspect, unrelated to the diseases of the body shell and meridians.

Combined with Ginseng, Liquorice Root, Ophiopogon Tuber, Rhubarb Rhizoma, Skullcap Root, it regulates the middle and tonifies qi; combined with Bupleurum, fluorite, Dried Rehmannia Root, it treats vomiting and counterflow. Dipped in rooster liver, it treats enuresis.

In yang medicine, it induces sweating and dispersion; in blood medicine, it warms and moves; in purgative medicine, it drains and benefits; in qi medicine, it expels pathogens through the exterior.

For phlegm cough and sore throat, blood deficiency internal dryness, pregnant women, postpartum blood heat, these four are contraindicated.

Aconite Lateral Root rescues yang within yin, Cassia Bark rescues yang within yang. Because Cassia's nature is light and uplifting, it can traverse horizontally to reach the surface, moving through all vessels.

Bencao Xinbian: Cassia Bark, pungent, sweet, fragrant, and spicy in taste, extremely hot in nature, sinking, yin within yang, slightly toxic. There are several types of Cassia Bark, the rolled ones are the best, the flat ones are second, both are usable. It enters the kidney, spleen, bladder, pericardium, and liver meridians. It nourishes the spirit, harmonizes the complexion, invigorates yang and resists aging, strengthens joints, promotes blood circulation, treats lower energizer deficiency cold, cures abdominal pain, diarrhea, and running-piglet in autumn and winter, benefits the water passages, warms the tendons and organs, breaks blood stasis and regulates menstruation, harmonizes the middle and tonifies qi, strengthens the defensive and nourishes the nutritive, calms vomiting and relieves pain. These are the functions of Cassia Bark, and people nowadays also know how to use it. However, the wonders of Cassia Bark are not limited to these. Its true wonder lies in its ability to guide the dragon-thunder fire to settle in the kidneys. The human body originally has two fires, one is the monarch fire, and the other is the ministerial fire. The monarch fire is the heart fire; the ministerial fire is the kidney fire. When the monarch fire is strong, the ministerial fire settles in the kidneys; when the monarch fire is weak, the ministerial fire rises to the heart. To make the fire that wants to reside in the heart settle back in the kidneys, it seems appropriate to tonify the monarch fire. However, the weakness of the monarch fire is not due to the heart, but due to the kidneys. When kidney qi interacts with the heart, the monarch fire is strong; when kidney qi separates from the heart, the monarch fire is weak. Therefore, to tonify the heart fire, one must tonify the kidney fire. When the fire in the kidneys is strong, the dragon-thunder fire will boil. If one does not tonify water to control the fire, but instead tonifies fire to assist the fire, it would be inappropriate. It is not known that kidney water cannot be generated without the ministerial fire, and kidney fire cannot be guided without the ministerial fire. Substantial fire can be drained, but deficient fire cannot be drained. Therefore, when the dragon-thunder fire boils, without Cassia Bark, how can it be guided to the utmost yin? It is like in spring and summer, when the ground is cold, the dragon-thunder emerges in the sky; in autumn and winter, when the ground is hot, the dragon-thunder hides in the ground. The human body is no different. When the lower energizer is hot, the upper energizer is naturally cold; when the lower energizer is cold, the upper energizer is naturally hot. This is an inevitable principle. To make the heat of the upper energizer turn into coolness, one must make the cold of the lower energizer warm again. Using Cassia Bark to greatly heat the life gate, the pudendal coldness in the kidneys will naturally dissipate. Using fire to attract fire, the dragon-thunder will be collected in an instant, with an inexplicable and natural magic. Thus, the heart palace becomes tranquil, and the fiery abode suddenly transforms into a cool breeze. However, the wonders of Cassia Bark are not limited to these. Its true wonder also lies in its ability to guide the dragon-thunder fire to ascend to the heart palace. The heart and kidneys are two inseparable entities. When kidney qi interacts with the heart, the day is peaceful; when heart qi interacts with the kidneys, the night is comfortable. If the kidneys separate from the heart, it is difficult to sleep well in the morning; if the heart separates from the kidneys, it is difficult to sleep soundly at night. There is fluid in the heart that always wants to interact with the kidneys, and there is essence in the kidneys that always wants to interact with the heart. But why do they always want to interact but ultimately cannot? One reason is the flaming up of the monarch fire, and the other is the sinking down of the ministerial fire. Look at the height of summer, when heaven does not interact with earth, and heaven becomes hot; in the depth of winter, when earth does not interact with heaven, and heaven becomes cold. The human body is no different. When the monarch fire is hot and can become cold, the heart naturally aids the kidneys; when the ministerial fire is cold and can become hot, the kidneys naturally aid the heart. This is also an inevitable principle. To make heart qi descend to interact with the kidneys, bringing peace to dreams, one must first make kidney qi ascend to interact with the heart, bringing tranquility to sleep. Using Cassia Bark with Coptis Rhizome, the flaming will not flame, and the sinking will not sink. The essence in the kidneys will naturally ascend to the heart palace, and the fluid in the heart will naturally descend to the kidneys. Using fire to aid water, the dragon-thunder will interact in an instant, with an inexplicable and natural magic. Thus, the heart ruler becomes joyful, and the dry chamber suddenly transforms into a land of blooming flowers. The wonders of Cassia Bark are such, and its other functions can also be understood by analogy.

Someone asked: Is it true that Cassia Bark can cause early abortion? The answer is yes. Then why did ancient people use it during pregnancy without causing miscarriage? The answer is: Cassia Bark affects the fetus when used alone as the main ingredient, and when combined with blood-moving drugs that promote early abortion, it can indeed cause rapid abortion. However, if Cassia Bark is used as a secondary ingredient in formulas that tonify qi and blood, how could it cause abortion? The reason it is avoided during pregnancy is not because it causes abortion, but because it may exacerbate fetal heat, leading to excessive fire symptoms in the newborn.

Someone asked: Since Cassia Bark warms and tonifies the life gate, which is related to the kidney meridian, why do some say it also affects the heart? Cassia Bark is not a heart meridian herb. If it doesn't belong to the heart meridian, how does it interact with the heart? The answer lies in the relationship between the heart and the pericardium. The pericardium is the minister of the heart, where the heart is the monarch fire and the pericardium is the ministerial fire. Ministerial fire cannot exist without monarch fire. Cassia Bark tonifies the ministerial fire. When it reaches the pericardium, it enhances the ministerial fire, which in turn interacts with the heart. This is how Cassia Bark affects the heart indirectly, not directly.

Someone doubted: Is it appropriate to use Cassia Bark in the Six-Ingredient Decoction, turning it into the Seven-Ingredient Decoction, a modification made by later generations by removing Aconite Lateral Root? The answer is: Using Cassia Bark in the Six-Ingredient Decoction is acceptable temporarily but not for long-term use. Cassia Bark warms the life gate fire and helps subdue the dragon and thunder fire. Temporarily, it can guide the thunder fire back to the kidneys. However, if used long-term in pills, its effect may weaken, failing to adequately warm and tonify the life gate fire, potentially causing the fire to rise uncontrollably. Therefore, it must be used with Aconite Lateral Root in pills for long-term use, ensuring that fire and water mutually support each other, keeping the dragon and thunder fire in check.

Someone doubted: If Cassia Bark is used in the Six-Ingredient Pill to supplement insufficient fire, then adding Ophiopogon Tuber and Schisandra Fruit to tonify lung qi might lead to excessive water supplementation, which seems inappropriate. However, adding these three ingredients to the Six-Ingredient Pill creates the Nine-Ingredient Rehmannia Pill, which is highly effective. The Six-Ingredient Rehmannia Pill, with added Cassia Bark and Schisandra Fruit, is called the Qi-Regulating Pill. This modification, removing Aconite Lateral Root and adding northern Schisandra Fruit, has profound significance. The Qi-Regulating Pill uses Cassia Bark and northern Schisandra Fruit to help subdue deficient fire. Cassia Bark in the Six-Ingredient Pill can guide fire back to its source but cannot generate fire to benefit the kidneys. With the help of northern Schisandra Fruit, the dragon and thunder fire is controlled, preventing it from rising uncontrollably. Schisandra Fruit also enriches essence, ensuring sufficient water. Thus, Cassia Bark neither needs to guide fire back nor risk raising it, making it highly effective in the kidneys. This is why the Qi-Regulating Pill is so remarkable. The Nine-Ingredient Rehmannia Pill further enhances this by adding Ophiopogon Tuber to tonify lung qi, allowing Schisandra Fruit to move between the lungs and kidneys, aiding both water generation and fire control. This demonstrates the versatility and efficacy of the Rehmannia Pill, evolving into even more effective forms.

Someone doubted: Why must Cassia Bark be used with Aconite Lateral Root in the Six-Ingredient Rehmannia Pill? Can't it be replaced with other herbs like malaytea scurfpea fruit or Aquilaria? The answer is: Cassia Bark can achieve results without Aconite Lateral Root, but Aconite Lateral Root cannot be effective without Cassia Bark. Aconite Lateral Root is mobile and does not stay in one place, while Cassia Bark is stable and does not move. Although Aconite Lateral Root is potent and can balance yin, it tends to rise without the stabilizing presence of Cassia Bark. Cassia Bark's steadfastness at the life gate ensures Aconite Lateral Root remains grounded. This is why Zhang Zhongjing used Aconite Lateral Root with Cassia Bark in the Eight-Ingredient Pill. Other herbs like malaytea scurfpea fruit or Aquilaria, while similar to Aconite Lateral Root, either sink too much or are too volatile, making Cassia Bark's balanced nature irreplaceable.

Some may doubt the use of Cassia Bark in the Eight-Ingredient Pill, which has been thoroughly explained by the master. However, the role of Cassia Bark in the Golden Chamber Kidney Qi Pill has not yet been clarified. Is it the same principle as in the Eight-Ingredient Pill? The Eight-Ingredient Pill uses Cassia Bark to strengthen the spleen by supplementing fire; the Kidney Qi Pill uses Cassia Bark to facilitate the bladder by supplementing fire. Although the Kidney Qi Pill uses Poria up to six taels, which undoubtedly promotes water circulation to benefit the bladder, the qi of the bladder must be aided by Cassia Bark to flow smoothly. Poria, when combined with Cassia Bark, warms the qi and transforms water. Although the pill contains Aconite Lateral Root, which can also direct kidney fire to the bladder, the nature of Aconite Lateral Root is to move without staying. Without the guiding effect of Cassia Bark, it may disperse throughout the body rather than specifically targeting the bladder to perform its diuretic function. Thus, the use of Cassia Bark in the Kidney Qi Pill has this additional significance.

Some may doubt that Cassia Bark in Duqi Pill may not necessarily be beneficial for promoting urination. Why is it that for treating water retention, Duqi Pill is not used, but Kidney Qi Pill is? Although Cassia Bark can enter the bladder and promote urination, it cannot expel water from the bladder. In Duqi Pill, Prepared Rehmannia Root is the principal herb, with Poria as an adjuvant, making it more tonifying than diuretic. In Kidney Qi Pill, Poria is the principal herb, with Prepared Rehmannia Root as an adjuvant, making it more diuretic than tonifying. When tonification outweighs diuresis, Cassia Bark assists Prepared Rehmannia Root in tonifying water, with tonification taking precedence over diuresis, and the diuretic effect is not diminished. When diuresis outweighs tonification, Cassia Bark assists Poria in promoting urination, with diuresis taking precedence over tonification, and the diuretic effect is truly beneficial. Therefore, for treating water retention, Kidney Qi Pill must be used, and Duqi Pill is not used.

Some may ask, Cassia Bark is used with Phellodendron Bark and Anemarrhena, and Dongyuan's treatment for bladder obstruction is remarkably effective. Thus, Phellodendron Bark and Anemarrhena have been used by predecessors, and one cannot blame Danxi. It is said: when bladder heat accumulation causes difficulty in urination, using Phellodendron Bark and Anemarrhena with the addition of Cassia Bark is a temporary remedy, and its proper use demonstrates Dongyuan's ingenuity. If, regardless of the presence or absence of heat, Anemarrhena and Phellodendron Bark are used indiscriminately, and Cassia Bark is omitted, even the water in the bladder cannot be passed, let alone tonify the kidneys. Humans are born of fire and die of cold; without fire at the life gate, the water in the bladder freezes, and water cannot be transformed. If Phellodendron Bark and Anemarrhena are used, adding more cold and coolness, the bladder will become even more icy and solid, making it impossible for even a drop of water to come out, leading inevitably to abdominal pain and death. The treatment method is to use five qian of Cassia Bark and one liang of Poria, taken hot, which will relieve abdominal pain upon swallowing and promote urination shortly after. Why is this? Because when the bladder is extremely cold, the heat of Cassia Bark is like the warmth of the Great Cold (24th solar term) bringing harmony, melting snow and ice in streams and ditches.

Some may ask, Cassia Bark is hot in nature, stationary and not dispersing, and can guide fire back to the life gate. But once it has returned, can it be used long-term? It is said: although Cassia Bark is stationary in nature, tonifying fire prevents the flame from rising. However, excessive tonification of fire can lead to excessive fire, potentially causing a spreading fire disaster. Generally, when fire is weak, adding fuel is beneficial, but when fire is strong, removing fuel is appropriate. One should not, due to Cassia Bark's stationary nature, only know to tonify fire and not to reduce fire.

Bencao Fenjing : Pungent and sweet, purely yang and very hot, enters the liver and kidney blood aspect. Tonifies the insufficiency of life gate ministerial fire, can suppress liver wind and support spleen earth, guides rootless fire to descend and return to its origin, treats chronic cold and deep-seated cold, unblocks blood vessels, induces sweating to expel nutrient-defense wind-cold.

Yixue Zhongzhong Canxilu : Pungent and sweet in taste, fragrant and dispersing in qi, very hot and purely yang in nature. Because it is the bark near the purgation part of the tree, it can descend, warm the dantian, strengthen primordial yang, and tonify ministerial fire. Its purple-red color also makes it excellent for assisting monarch fire, warming and unblocking meridians and vessels, treating blood vessel obstruction due to cold, hence effective for joint and limb pain and white ulcers in sores. Wood withers when it gets Cassia Bark, and its pungent taste belongs to metal, making it good for pacifying liver wood, treating liver qi excess and frequent anger. If the liver has heat, it can be assisted by herbs like Gentian and Peony Root. Shennong Bencao Jing says it is the herald and envoy of all herbs, because its fragrant and dispersing qi can quickly reach all parts internally, from the zang-fu organs, sinews, and bones, to externally the meridians, striae, and interstices. Therefore, where other herbs cannot penetrate, Cassia Bark can guide them to penetrate.

bubble_chart Modern Pharmacology

1. Cinnamaldehyde in Cassia Bark can enhance the contractility of isolated hearts, improve myocardial blood supply, and has a protective effect on the myocardium. Cassia Bark has a transient dilating effect on coronary and cerebral blood vessels.
2. Cassia Bark can prevent the formation of venous or arterial thrombosis.
3. Cassia Bark has sedative, anticonvulsant, analgesic, and central antipyretic effects, and can produce centrally originated EEG activation.
4. Cassia Bark inhibits the autonomous contraction of gastrointestinal smooth muscle and has a significant therapeutic effect on the digestive system, especially on gastric ulcers.
5. Cassia Bark promotes the immune system.
6. Cassia Bark has a protective effect on adrenal cortical function and a certain influence on the endocrine system.
7. Cassia Bark has anti-stress and anti-radiation effects.
8. Cassia Bark has a broad spectrum of antifungal and antibacterial effects.
9. Cassia Bark can counteract the vasoconstrictive effect of prostaglandins and improve the microcirculation function of the uterus.