Aconite (Fu Zi, 附子) is a processed product derived from the lateral roots of the tuberous root of the Aconitum plant, which belongs to the Ranunculaceae family. The main root (mother root) is called Chuan Wu (川乌), and both Chuan Wu and Aconite come from the same plant.
Ancient scholars were already aware of the toxicity of Aconite. The Huai Nan Zi states: “Among all things in the world, none is more dangerous than the poison of Aconite.” The Guang Ya notes: “The poison of Aconite is the same as that of Fu Zi.” It takes one year to become Zhi Zi (子), two years to become Wu Hui (乌喙), three years to become Fu Zi (附子), four years to become Wu Tou (乌头), and five years to become Tian Xiong (天雄). However, Aconite is also a valuable medicinal herb; the Huai Nan Zi records that “Tian Xiong and Wu Hui are the most dangerous, but a good doctor can save lives.”
The medicinal history of Aconite is long, and its efficacy and toxicity have always been a focal point of research and debate among many medical scholars.
01
The Efficacy of Aconite
The Ming dynasty physician Zhang Jingyue listed Aconite as one of the “Four Essentials of Medicine,” praising that “Ginseng and Shud Di (熟地) are the good ministers of a peaceful world; Aconite and Rhubarb are the good generals of a chaotic world.”
Aconite has the effects of reviving yang, supplementing fire to assist yang, dispelling cold, and alleviating pain.
-
Reviving Yang
Aconite is known as the “best medicine for reviving yang” and is essential for treating the collapse of original yang, cold skin, and weak pulse. The Si Ni San (四逆汤) in the Shang Han Lun is a classic formula for reviving yang, combining Aconite with Gan Jiang (干姜) and Zhi Gan Cao (炙甘草) to enhance efficacy while reducing toxicity. It is primarily used to treat symptoms caused by excessive internal cold and weak yang, such as cold limbs, aversion to cold, fatigue, vomiting, diarrhea, profuse sweating leading to yang collapse, and a faint pulse. This formula has been used since its creation for treating critical conditions.
-
Supplementing Fire to Assist Yang
Aconite is hot and spicy, and its nature is good at moving. It can circulate through the twelve meridians, warming the body’s yang, assisting heart yang to open the vessels, warming spleen yang to dispel cold, and supplementing kidney yang to enhance fire, while also expelling surface cold. It can be used to treat insufficient heart yang, chest obstruction and pain, cold-induced vomiting and diarrhea, abdominal cold pain, kidney yang deficiency, impotence, cold water retention, and external invasion due to yang deficiency.
-
Dispelling Cold and Alleviating Pain
Aconite has a strong and aggressive nature, capable of warming and unblocking the meridians, expelling wind, cold, and dampness from the channels, and has a strong effect in dispelling cold and alleviating pain, making it suitable for treating pain due to wind-cold-dampness obstruction.
02
The Toxicity of Aconite
Aconite is toxic; the Book of Han records a case of “Aconite poisoning.” According to the Book of Han: Biographies of the Empresses, during the reign of Emperor Xuan of Han, General Huo Guang wanted his daughter to become empress, so he coerced the physician Chunyu Yan to harm Empress Xu after she gave birth. Chunyu Yan secretly mixed the prepared Aconite into the medicine that Empress Xu was to take, and shortly after taking the medicine, she fell into a coma and died.
The toxic components of Aconite include aconitine, among others. Oral intake of 0.2 mg of aconitine can cause poisoning, with a lethal dose being 3-4 mg. Aconite poisoning can affect multiple systems, including the nervous, circulatory, and respiratory systems, presenting symptoms such as numbness of the lips and limbs, nausea, vomiting, palpitations, shortness of breath, agitation, and even coma, with occasional convulsions. In severe cases, it can lead to cardiac arrest and respiratory failure. Aconitine has significant cardiac toxicity, with ECG findings showing transient bradycardia, atrial and ventricular premature contractions, tachycardia, as well as non-paroxysmal ventricular tachycardia and ventricular fibrillation.
03
Detoxification Measures
Ancient scholars were aware of the toxicity of Aconite, and the Shen Nong Ben Cao Jing classified Aconite as a lower-grade herb, highly toxic, and unsuitable for long-term use. Throughout history, physicians have paid great attention to its toxicity and have attempted various measures to reduce its toxicity while pursuing optimal efficacy.
-
Processing to Reduce Toxicity
Raw Aconite is highly toxic and is rarely used clinically; mostly, its processed forms are utilized. The processing history of Aconite is long and complex, with physicians continuously exploring new processing methods over the ages.
The processing methods of Aconite first appeared in the Jin Kui Yao Lue: “All must be broken, not chewed, either processed or raw, and the skin must be removed.” This mentions the methods of “processing” and “removing the skin.” From the Wei and Jin dynasties to the Tang dynasty, methods such as roasting, stewing, and frying were added, along with water-fire co-processing with auxiliary materials. The range of auxiliary materials was also expanded to include black beans, salt, vinegar, and ginger. During the Ming and Qing dynasties, the processing techniques focused on soaking and boiling, with direct heating methods being reduced, mostly involving soaking followed by stewing or processing; the auxiliary materials also became simplified, often including licorice and black beans to mitigate toxicity, a practice that continues to this day. The Chinese Pharmacopoeia (2020 Edition) lists processed varieties of Aconite, including Hei Shun Pian (黑顺片), Bai Fu Pian (白附片), Dan Fu Pian (淡附片), and Pao Fu Pian (炮附片).
During the processing, the highly toxic diester aconitine is hydrolyzed into benzoyl monoester alkaloids, which are further hydrolyzed into alcohol amine-type alkaloids, thereby reducing toxicity.
-
Compatibility to Reduce Toxicity
Through reasonable compatibility, the toxicity and adverse reactions of Aconite can be significantly reduced. When combined with Gan Jiang and Gan Cao, the toxicity of Aconite can be lowered. The flavonoids in licorice can counteract the arrhythmias caused by aconitine. The components of dry ginger mainly include volatile oils and gingerols, which may have a restraining and resolving effect on aconitine, thus inhibiting its toxicity. Studies have shown that Aconite combined with Da Huang (大黄), Huang Qin (黄芩), Huang Lian (黄连), and Zhi Zi (栀子) also has certain detoxifying effects; Aconite combined with Ren Shen (人参), Huang Qi (黄芪), Fang Feng (防风), and Yuan Zhi (远志) also exhibits detoxifying properties.
-
Dosage and Preparation Methods
Aconite is a toxic herb, and excessive use can lead to poisoning. The Chinese Pharmacopoeia stipulates a dosage of 3-15 g for Aconite, but due to varying understandings and clinical experiences among physicians throughout history, there is controversy regarding its dosage range. If using beyond the conventional dosage, adjustments must be made based on the patient’s condition and reactions after taking the medicine to ensure safety.
Aconite is hot and toxic; when used clinically, it must be boiled for a long time, especially when used in large doses. Modern research has also proven that prolonged boiling can reduce the toxicity of Aconite.
04
How to Avoid Poisoning
Cases of poisoning due to improper use of Aconite are not uncommon. The reasons often stem from self-medication, improper preparation, inappropriate processing, excessive use, or improper compatibility. Once poisoning symptoms appear, the medication should be stopped immediately, and for mild reactions, inducing vomiting or gastric lavage can help eliminate the toxins. Treatment for Aconite poisoning primarily involves symptomatic treatment in Western medicine, but can also include the use of licorice and mung beans to enhance detoxification effects.
To avoid Aconite poisoning, attention should be paid to the following aspects:
-
Avoid self-purchasing and using Aconite; it must be used under the guidance of a physician after proper diagnosis;
-
Do not use raw Aconite for internal decoction; only processed Aconite should be used;
-
When using processed Aconite, start with a small amount and adjust the dosage based on the patient’s condition and reactions; large doses must be boiled for over one hour.
References
Chinese Pharmacopoeia (2020 Edition)
Clinical Medication Guidelines of the Chinese Pharmacopoeia
—END—
Text: Zhang Pei
Proofreading: Clinical Pharmacy