Fuzi (Aconiti Radix) and Chuanwu (Chuanwu) from the previous discussion on dispelling wind, dampness, and cold originate from the same plant. Chuanwu is the main root, while the child root that grows alongside it is called Fuzi.
However, in commercial herbal materials, it is often sliced, so prescriptions frequently refer to it as Fu Pian (Fuzi slices).
During processing, a coloring solution made with vegetable oil and brown sugar is used to dye it a dark tea color, which is called Hei Fu Pian (black Fuzi slices); if sliced along the length, it is called Shun Pian (longitudinal slices); if sliced across, it is called Heng Pian (transverse slices).
There is a type called Huang Fu Pian (yellow Fuzi slices), which is dyed yellow and cut transversely; Bai Fu Pian (white Fuzi slices) is cut longitudinally, steamed, and then fumigated with sulfur to lighten its original color.
Fuzi must undergo special cultivation and processing in its production area, which includes specific field management. After harvesting, it is soaked in brine, which contains many chemical elements, and then processed through the aforementioned steps.
Since the Song Dynasty, Fuzi has been a well-known medicinal material from Sichuan, particularly from a place called Jiangyou in Mianyang City, which was formerly known as Zhangming. The production area is centered around this region, and there has been a record of Fuzi from Zhangming since the Song Dynasty.
In the past, Fuzi was processed by individual households in small workshops. Due to commercial competition, there were many specifications, including yellow, white, black, longitudinally cut, and transversely cut, as well as thinner slices made with a plane, known as Pao Pian (shaved slices).
In the northwest of Sichuan, during the harvesting season for Fuzi, there is often a lot of rainy weather. Some small workshops cannot keep up with processing, so similar to how Sichuan people make pickles, after digging up Fuzi and removing the outer skin and dirt, they clean it appropriately and soak it in brine to prevent spoilage and rot, allowing it to be stored for one to two years. This is called Yan Fuzi (salted Fuzi).
When using Yan Fuzi, it still needs to be sliced and soaked in water to remove the saltiness, which is called Dan Fu Pian (light Fuzi slices).
Generally, when prescribing this herb, it is not referred to as Fuzi, but rather as Fu Pian, Bai Fu Pian, Huang Fu Pian, Hei Fu Pian, etc., because it is not the whole Fuzi root but rather the processed and sliced herbal material, hence the term Fu Pian.
The reason for explaining these various specifications of commercial herbal materials, including the traditional Pao Fuzi (processed by burning) and the modern microwave-processed Fuzi, is due to the need for commercial competition, which has no direct correlation with its medicinal efficacy.
However, some people claim that Yan Fuzi is intentionally made to “enter the kidney through salt,” but this is not the case; it is due to the inability to process it, as the quantity harvested is too large. Influenced by the Sichuan method of making pickles, it is placed in brine to prevent spoilage, and it is not intended to be made for the purpose of “entering the kidney through salt.”
Fuzi is also a very important herb. As I mentioned when discussing Dahuang (Rhubarb), it is one of the four essential herbs. Fuzi is not only a key herb among warming herbs but also a significant herb in traditional Chinese medicine.
The effects of Fuzi are primarily manifested in three aspects.
The first aspect is particularly special, called Hui Yang Jiu Ni (Returning Yang and Rescuing from Reversal). Hui Yang Jiu Ni refers to a therapeutic effect for the condition of Yang deficiency, or a therapeutic efficacy.
What is Yang deficiency? It is a condition where some individuals, due to prolonged illness, have their Yang energy continuously depleted, leading to a final collapse of Yang energy.
Another scenario is suddenly suffering from an acute illness, such as severe vomiting, diarrhea, or profuse sweating, where Yang energy escapes with Yin, resulting in Yang deficiency.
The clinical manifestations of Yang deficiency are typically characterized by two symptoms: cold extremities and a weak, almost imperceptible pulse.
The term “Hui” in this context means “to be without”; in ancient texts, it is explained as “Hui, meaning none.” The meaning of Yang deficiency is as if the Yang energy has disappeared, indicating that the Yang energy has been completely depleted.
Why does this occur? The depletion of Yang energy primarily results from the decline of the Yang energy of the kidney and heart, as the basic function of kidney Yang is to warm the body. The Yang energy in the kidney is fundamental to maintaining the body’s appropriate temperature.
When kidney Yang declines, it cannot warm the body, leading to cold extremities. In milder cases, it may only affect the fingers and toes; in severe cases, it may extend to the upper limbs beyond the elbows and the lower limbs beyond the knees, eventually resulting in a cold sensation throughout the body. Cold extremities are a manifestation of kidney Yang’s inability to warm the body.
The heart governs the blood vessels, and when the heart’s Yang energy declines, it cannot propel the blood, leading to abnormal blood flow and a weak pulse.
This indicates that the fundamental pathology is the decline of the Yang energy of the heart and kidney, which has reached a critical point, almost to the point of extinction. This is what is referred to as Yang deficiency in traditional Chinese medicine.
In this situation, Fuzi is the first herb in traditional Chinese medicine that can “return Yang and rescue from reversal.”
Because Fuzi’s ability to return Yang and rescue from reversal is unparalleled, no other herb can replace it. Although it is toxic, in clinical practice, it can significantly restore the Yang energy that is about to be lost, which is essentially restoring life. It has historically been an important herb for emergency treatment of Yang deficiency.
From ancient times to the present, especially in ancient medical conditions, treatment of Yang deficiency relied heavily on oral administration of Fuzi and similar herbs.
However, Fuzi requires prolonged decoction. If a patient is in a critical condition, boiling it for a long time and then allowing it to cool before administering can take a considerable amount of time, which may not be sufficient in emergencies. In ancient times, this was the only medical condition available.
Currently, Fuzi is available in emergency formulations, such as Shenfu injection. Even now, although comprehensive emergency measures can be taken for Yang deficiency, combining traditional and Western medicine, such as intravenous fluids, blood transfusions, and some Western medications for severe vomiting, diarrhea, profuse sweating, or bleeding, the effectiveness has greatly improved.
However, the clinical value of Fuzi in returning Yang and rescuing from reversal still exists. Therefore, in many hospitals, if a typical case of Yang deficiency occurs, while other measures are taken, the use of Fuzi-related injections remains quite widespread, achieving a significant effect in returning Yang and rescuing from reversal. Thus, it is the most important herb in traditional Chinese medicine for returning Yang and rescuing from reversal, with reliable and unique therapeutic effects for Yang deficiency.
Although Fuzi is the primary herb for returning Yang, its strength alone may not be sufficient, as the condition may be too severe, and Yang energy may be extremely deficient. The process of restoring Yang energy also takes time, which is relatively slow compared to herbs like Ganjiang (Dried Ginger).
It also has a certain level of toxicity. Therefore, in treating Yang deficiency, it is not common to use Fuzi alone; it is often combined with Ganjiang and Gancao (Licorice), which is the basis of Zhang Zhongjing’s Si Ni Tang (Four Reversal Decoction).
The combination of Fuzi with Ganjiang and Gancao serves two purposes: to reduce the toxicity of Fuzi and to enhance its efficacy. They have a complementary relationship; Fuzi is antagonistic to Ganjiang, and it can be said that Fuzi is afraid of Gancao; Gancao or Ganjiang can counteract the toxicity of Fuzi, reducing its harmful effects.
Secondly, it enhances the effect, as they have a synergistic relationship that can strengthen the effect of returning Yang and rescuing from reversal. Ganjiang also has a Yang-replenishing effect; modern research shows that Gancao can also enhance Fuzi’s effect in returning Yang and rescuing from reversal.
Additionally, while Fuzi returns Yang, its action is relatively slower compared to Ganjiang. Therefore, some texts state that Fuzi’s nature is more conservative, while Ganjiang is more active, quickly exerting its Yang-replenishing effect. On the basis of initial effectiveness, Fuzi also begins to take effect, allowing for a more rapid and sustained medicinal effect.
Due to these multiple advantages, they are combined together. The purpose of the combination of Fuzi and Ganjiang is to enhance efficacy and reduce toxicity, which is a very special and important combination that must be remembered.
In clinical cases of Yang deficiency, it is not solely a decline in kidney Yang or heart Yang; there may also be a depletion of Yuan Qi (original Qi), which is referred to as Yang Qi depletion. In this case, simply using Fuzi to return Yang is not targeted for the depletion of Yuan Qi, so it is necessary to add Ren Shen (Ginseng). The combination of Ren Shen and Fuzi is known as Shenfu Decoction, and the current injection formulation is based on this prescription.
Shenfu injection is currently produced by several pharmaceutical companies nationwide and can be administered intravenously, allowing for a rapid return of Yang and rescue from reversal. This formulation is suitable for emergency treatment.
In summary, the situation of Fuzi returning Yang and rescuing from reversal is as described, but it is not easy to use effectively in clinical practice. Ancients said that Fuzi is the most useful herb, yet also the most difficult to use.
The most useful aspect refers to its ability to save lives in cases of Yang deficiency, which has significant clinical application value.
On the other hand, it is considered difficult to use because it treats critical conditions and is toxic. The requirements for the method of use, dosage, and combinations are very precise; any slight negligence may lead to unimaginable consequences, which is why it is regarded as difficult to use. However, the utility of Fuzi should be fully acknowledged.
The second effect is Bu Huo Jiu Yang (Replenishing Fire and Rescuing Yang), which refers to replenishing the fire of the Mingmen (Gate of Life). Replenishing the fire of the Mingmen actually refers to the Yuan Yang of the human body, which is kidney Yang.
In this context, Fuzi’s role in replenishing fire and assisting Yang refers to replenishing Yuan Yang, so it can be used for all forms of Yang deficiency. Therefore, the second application mentioned in texts is for Yang deficiency syndromes.
Among Yang deficiency syndromes, the first is kidney Yang deficiency. Due to the various physiological functions of the kidney, kidney Yang deficiency can manifest in multiple clinical symptoms, and Fuzi can generally be used. Kidney Yang deficiency primarily fails to warm the body, leading to cold intolerance and cold limbs, as well as lower back and knee pain.
Additionally, growth and development may be delayed, leading to premature aging; or kidney governs water, leading to abnormalities such as edema, frequent urination, or nocturia; in elderly individuals, it may even lead to incontinence; kidney governs reproduction, and kidney Yang deficiency can result in reduced reproductive function and sexual dysfunction; the kidney also governs the reception of Qi, and when it fails to do so, it can lead to shortness of breath, with more exhalation and less inhalation, known as Xu Chuan (deficiency asthma); kidney also warms the spleen Yang, and in cases of spleen and kidney Yang deficiency, it can lead to persistent diarrhea. Fuzi can be used in all these cases.
However, the most effective and useful effect is likely in improving kidney Yang deficiency’s inability to warm the body. As for the symptoms caused by Yang deficiency in other aspects of the kidney, further research may be needed to determine what issues Fuzi can address.
However, from ancient to modern clinical applications, Fuzi has been widely used for all forms of kidney Yang deficiency, regardless of the symptoms presented, and it likely has varying degrees of efficacy.
For example, it is used for generalized edema and urinary difficulties due to kidney Yang deficiency; it is also used for clear, frequent urination and nocturia due to kidney Yang deficiency. It is a widely used herb for kidney Yang deficiency, and future discussions on Yang-replenishing herbs should focus on the manifestations of Yang deficiency and how to optimally select and combine them.
Secondly, it can be used for spleen Yang deficiency, which can lead to abdominal cold pain, diarrhea, and poor appetite. It can nourish both spleen and kidney, so it can be used for both spleen and kidney deficiency, as well as for cases primarily involving spleen Yang deficiency.
Spleen Yang deficiency is generally a further development of spleen Qi deficiency, so it often needs to be combined with Qi-replenishing herbs, such as Ren Shen and Bai Zhu (White Atractylodes), which is the guiding principle of the Li Zhong Tang (Regulating the Middle Decoction) that combines Fuzi with Ren Shen and Bai Zhu.
It can also be used for heart Yang deficiency. Yang deficiency is already present in cases of Yang deficiency, and general heart Yang deficiency can present with mild symptoms such as spontaneous sweating and palpitations.
In severe cases, it may lead to chest pain, which is a manifestation of cold. When using Fuzi, it is often combined with blood-activating herbs or warming herbs like Rougui (Cinnamon) and Guizhi (Cinnamon Twig).
For example, in treating Yang deficiency with a cold, the formula Ma Huang Fuzi Xi Xin Tang (Ephedra, Aconite, and Asarum Decoction) also uses Fuzi to replenish Yang energy. Additionally, for Wei Yang (defensive Yang) instability, leading to spontaneous sweating, Qi Fu Tang (Qi and Fu Decoction) can be used, which combines Fuzi with Huang Qi (Astragalus) to stabilize the exterior and stop sweating.
In summary, Fuzi can almost always be used for any form of Yang deficiency, and it can be used to replenish fire and assist Yang in all deficiency-cold syndromes.
The third effect is San Han Zhi Tong (Dispelling Cold and Alleviating Pain). This refers back to our previous overview; generally speaking, dispelling cold and alleviating pain means that this herb can warm the interior and warm the meridians, having a broad effect of warming the interior and dispelling cold, or warming the interior and alleviating pain.
For Fuzi’s ability to dispel cold and alleviate pain, it can first warm the interior and be used for stomach cold or spleen-stomach deficiency cold. If it is Yang deficiency, it can be used, as already mentioned in the Yang-replenishing section.
If it is not Yang deficiency but a condition of excess, such as excessive cold evil, leading to abdominal cold pain, Fuzi can still be used.
In addition to warming the interior, Fuzi can also warm the meridians, widely used for cold pain in the limbs or headaches caused by cold in the meridians.
A particularly special warming and dispelling cold effect of Fuzi is its similar action to Wutou (Aconite) in dispelling wind-dampness, so it is also a good herb for dispelling wind-dampness and alleviating cold pain, especially in cases of wind-damp cold bi syndrome with accompanying Yang deficiency.
While Fuzi is not as effective as Wutou in dispelling wind-dampness, it can still be used and has a similar effect.
The application of the third effect addresses interior cold conditions as an excess syndrome; the second effect also addresses interior cold conditions as a deficiency syndrome.
Therefore, the ancients said that Fuzi can be used for “any cold condition, regardless of deficiency or excess.” One is for deficiency-cold syndromes, and the other is for excess-cold syndromes; the excess syndrome is for warming the interior and dispelling cold, while the deficiency syndrome is for warming and replenishing Yang energy. The main effects of Fuzi are in these three areas, which correspond directly and are easy to remember.
There are also some noteworthy issues regarding the usage, dosage, and precautions for Fuzi. First, the dosage is typically 3-9 grams.
The dosage of Fuzi varies greatly across the country. In some coastal areas of Jiangnan, the general dosage tends to be lower, as the climate is hot, and people are prone to heat and sweating, often leading to fluid damage. Doctors in these areas are particularly cautious with Fuzi, especially in hot weather, where it is common to use only a few grams.
However, in the southwestern region, many clinical doctors feel that using only a few grams may not achieve the desired effect, so it is common to use Fuzi at 30 grams, especially in Sichuan and Yunnan. In the 1950s and 1960s, a well-known doctor in Yunnan, known as the “Fire God,” Wu Peiheng, often prescribed Fuzi at 100-500 grams, which was not uncommon. The key factor is prolonged decoction; if Fuzi is used at 3-5 grams but not decocted for a long time or processed, it can easily lead to toxicity. If a large amount is used, boiling for 3-5 hours, sometimes from morning until afternoon or from evening until the next morning, using 100-200 grams of Fuzi may not cause any toxic reactions.
The key is whether such a large amount should be used; in reality, it may not be fully utilized. I want to clarify that I am not advocating for everyone to use more or heavier doses, especially for beginners. The dosages in textbooks should be considered practical and should be the primary reference. After gaining experience, if one feels it is necessary, the dosage can be slightly increased.
Most of the time, the solvent in decoctions is limited; with a limited solvent, the amount of herbs used cannot exceed a certain limit, and their solubility is also limited. Therefore, we need to treat the dosage correctly; excessive dosages can be unsafe and wasteful, while excessive caution can also affect efficacy.
Fuzi requires prolonged decoction, so within a certain range, using a bit more should be quite safe.
Its warming and drying properties are not as intense as those of Ganjiang or Hu Jiao (Black Pepper), so in southwestern folk medicine, Fuzi is often used as a food therapy ingredient in winter, with larger amounts used when stewing lamb. Many people do not have obvious Yang deficiency but do not experience adverse warming and drying reactions after using it, indicating that Fuzi can be considered safe as long as it is used reasonably. The key is prolonged decoction until there is no trace of numbness, similar to Wutou.
Although the combinations and processing of Fuzi can reduce its toxicity, the most effective method is to heat and decoct it. Therefore, Fuzi in pill or powder form must be used with caution; without water and high heat to hydrolyze it, its toxicity is significant.
I have seen a case of Fuzi poisoning where someone ate a lot of Fuzi while stewing meat and had no reaction, but after eating a piece of Fuzi that was not submerged in water, they immediately felt unwell, first experiencing numbness, followed by heart-related adverse reactions such as arrhythmia. This was caused by that piece of Fuzi that was not cooked in water. This example illustrates the importance of thorough decoction in water for detoxification.
Additionally, the so-called drying heat injures Yin and assists heat, which is not suitable for those with Yin deficiency and Yang excess, and pregnant women should not use it. These are common contraindications for this category of herbs and are not specific to Fuzi.
All the content regarding Fuzi is as stated in our textbooks. It is mentioned that Fuzi is one of the eighteen antagonistic herbs. Our “Clinical Chinese Herbal Medicine” does not affirm or deny this.
In the sixth edition of the textbook, it was listed as one of the eighteen antagonistic herbs because the original pharmacopoeia included a category of Wutou herbs that should not be used with Banxia (Pinellia), Guo Lou (Trichosanthes), Beimu (Fritillaria), Bai Lian (White Lotus), and Bai Ji (Bletilla). Since Fuzi is also a Wutou herb, it is important to be aware of this.
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Excerpted from “Zhang Tingmo’s Lectures on Chinese Herbal Medicine,” copyright belongs to the original author. This article was edited and published by the WeChat platform of the Chinese Journal of Traditional Chinese Medicine (CJCMMYC). Please respect the labor of others, and when reprinting on public accounts, be sure to indicate the source and WeChat ID.
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