，味苦，气寒，有小毒。一云∶性热，无毒者非。入肾。疗暴中风邪，口眼 斜，
治久
湿湿痹，腰脚酸痛，主热匿烦满。然散人之真气，尤不宜服，不宜用，而入之兹编者，何也
？盖肾经之药，药品中尤少，肾犯风邪湿气，又尤难治，姑
存之，以治肾中风湿之病。不知何故古人尽称此品，近人亦多乐用之，且有赞其百服则耳目
聪
明，千服则须发乌黑，追风逐湿。犹作泛等闲语，此真杀人之语也。余客闽，有一贵人卒然
中风，余切其脉，绝无浮象，甚微细欲绝。余曰∶此真气虚绝将脱之症。急用参、 、熟地
、山茱、麦冬、五味之药，大剂投之，一剂而神思清，再剂而语音出。余咎其平日之纵欲也
。贵人曰∶余已绝欲数年矣，尚恐欠健，日服补剂，病乃中风。而先生绝不治风，竟用大补
血气、填益精髓之品，以救吾命，此仆所不解也。余问所用是何补药。曰∶客有劝余服
丸者，服之已一年矣。余曰∶是矣。 耗人真气，岂可常服。曰∶然。余服之，久不见功
效，心窃疑之，今闻先生之教，乃恍然大悟，瓶中余药，呼儿尽弃之。恪遵吾方而全愈。嗟
乎！贵人幸遇吾，得不死。此吾所见治而知 之杀人也。而余所不及是闻者，不甚多乎。
虽然， 亦非能杀人，不善用之，多致杀人耳。而善用之若何。中风之症，必问其腰间素
有水湿之癣否。有水湿之癣，又必问其肾囊之干湿若何。肾中有风，其人必然腰痛而重；肾
中有湿，其人必然囊破而疮。即用 ，亦必与人参、白术大剂共用，又何至误杀人乎。至
于湿痹腰脚酸疼之症，又必加入薏仁、茯苓、黄 、芡实同施，始万全也。
或问 为举世嘉尚，而先生弃之至此乎。夫 未尝无功，余虑人误认补味，而常用
之耳
。风湿入肾者尤难治，存 而不删去者，正备妙用耳。不然，防己可祛肾内之风湿，存防
己可，必复取 ，正以 功用胜防己，其耗散精血，亦逊于防己。所以，存防己而仍存
。盖防己治肾内之风湿，止可一用以出奇，不可再用以贻害。若 则不妨一用，而至
于再用，但不可久用耳。
（乌头）味苦，气寒，有小毒。另一种说法称其性热、无毒，这是不对的。归入肾经。治疗突然发作的中风邪气，口眼歪斜；治愈长期的风湿痹痛，腰脚酸痛；主治热邪潜伏导致的烦闷胀满。然而它会耗散人的真气，尤其不宜服用，也不宜使用。既然这样，为什么把它收录在本编中呢？大概是因为补肾的药物在药品种类中特别少，而肾脏遭受风邪湿气侵袭，又特别难以治疗，所以姑且保留它，用来治疗肾中的风湿疾病。
不知道什么原因，古人全都称赞这种药材，近人也大多乐于使用它，甚至有人赞美说“百次服用则耳目聪明，千次服用则须发乌黑”，能追风逐湿。这些不过是泛泛的闲话，这真是杀人的话语啊。我旅居福建时，有一位贵人突然中风，我切他的脉象，完全没有浮象，非常微细几乎要断绝。我说：“这是真气虚极将脱的症状。”急忙用人参、附子、熟地黄、山茱萸、麦冬、五味子的药物，大剂量投服，一剂后神志清醒，两剂后声音发出。我责怪他平日纵欲过度。这位贵人回答说：“我已经戒欲好几年了，还担心身体不健壮，每天服用补药，结果得了中风。而先生完全不治风，竟然用大补气血、填益精髓的药物来救我的命，这是我不能理解的。”我问他用的是什么补药。他说：“有位客人劝我服用乌头丸，已经服了一年。”我说：“这就是原因了。乌头耗损人的真气，怎么可以长期服用。”他说：“是的。我服用它，长久不见功效，心里暗自怀疑，现在听了先生的教导，才恍然大悟，把瓶中剩下的药，叫儿子全部扔掉。严格遵循我的方子而完全痊愈。唉！这位贵人幸好遇到我，才得以不死。这是我亲眼所见因误用乌头而知晓它是杀人之物的案例。而我所没来得及听闻类似情况的，难道还少吗？
虽然如此，乌头也不是能直接杀人，是不善于使用它，多导致杀人罢了。那么怎样才算善于使用呢？对于中风的病症，必须询问患者腰间平时是否有水湿之癣。如果有水湿之癣，又必须询问患者阴囊的干湿情况如何。肾中有风，这个人必然腰痛且沉重；肾中有湿，这个人必然阴囊破溃生疮。即使使用乌头，也必须与人参、白术大剂量共用，又怎么会误杀人呢？至于风湿痹痛、腰脚酸疼的病症，又必须加入薏苡仁、茯苓、黄芪、芡实共同施用，才开始万无一失。
有人问：乌头被举世推崇，而先生却抛弃它到这种地步吗？乌头未曾没有功劳，我担心人们错误地把它认作补药，而经常使用它罢了。风湿侵入肾脏的尤其难治，保留乌头而不删去，正是为了准备它的妙用。不然的话，防己也可以祛除肾内的风湿，保留防己是可以的，但还要取用乌头，正是因为乌头的功用胜过防己，但它耗散精血的程度，也次于防己。所以，保留防己而仍然保留乌头。大概防己治疗肾内的风湿，只可一次使用以出奇制胜，不可再次使用以遗留祸害。若乌头则不妨使用一次，至于再次使用，只是不可以长期使用罢了。
(Aconite) has a bitter taste and cold nature, with slight toxicity. Another claim states it is hot in nature and non-toxic, which is incorrect. It enters the Kidney meridian. It treats sudden onset of wind-pathogen stroke, deviation of the mouth and eyes; cures chronic wind-damp bi-syndrome, soreness and pain in the waist and feet; and governs heat lurking causing irritability and fullness. However, it scatters the body's true Qi (Vital Energy), making it particularly unsuitable for consumption or use. Since this is so, why is it included in this compilation? Presumably because herbs targeting the Kidney are especially scarce among medicinal substances, and diseases where the Kidney is invaded by wind-pathogen and dampness are particularly difficult to treat. Thus, it is tentatively retained to treat wind-damp diseases within the Kidney.
It is unknown what cause led ancients to universally praise this herb, and modern people also tend to use it readily. Some even praised it saying, "After taking it a hundred times, hearing and vision become sharp; after a thousand times, beard and hair turn black," claiming it can chase wind and expel dampness. These are merely casual remarks; such statements are truly killers' words. While residing in Fujian, a nobleman suddenly suffered from stroke. I palpated his pulse and found no floating quality at all; it was extremely fine and nearly imperceptible. I said, "This is a syndrome of extreme deficiency of True Qi about to collapse." I urgently prescribed large doses of Ginseng Radix et Rhizoma (Renshen), Prepared Aconite Root (Fuzi), Prepared Rehmanniae Radix (Shudihuang), Cornus Officinalis Fruit (Shanzhuyu), Ophiopogon Tuber (Maidong), and Schisandra Berry (Wuweizi). After one dose, his mental clarity returned; after two doses, his voice emerged. I blamed him for his past indulgence in sexual activity. The nobleman replied, "I have abstained from sexual activity for several years, yet still feared my health was lacking, so I took tonics daily, resulting in stroke. That you did not treat the wind at all, but instead used large doses of herbs to greatly tonify Qi and Blood, and fill and benefit essence and marrow to save my life, is something I do not understand." I asked what tonic he had used. He said, "A guest advised me to take Aconite pills, which I have taken for a year." I said, "That explains it. Aconite depletes the body's True Qi; how can it be taken regularly?" He said, "Indeed. I took it, but saw no effect for a long time, and secretly doubted it. Now, hearing your teaching, I am suddenly enlightened. I called my son to discard all remaining medicine in the bottle. Strictly following your prescription, I made a complete recovery. Alas! This nobleman fortunately met me and avoided death. This is a case I witnessed personally, knowing through treatment that Aconite is a killer. And those similar cases I failed to hear of beforehand—are they not numerous?
Nevertheless, Aconite itself does not kill; it is the improper use of it that often leads to death. So, how should it be used properly? In cases of stroke, one must ask if the patient has historically had water-damp eczema on the waist. If there is water-damp eczema, one must further ask about the dryness or moisture of the scrotum. If there is wind in the Kidney, the person will inevitably suffer from sore and heavy lower back pain; if there is dampness in the Kidney, the person will inevitably suffer from scrotal ulceration and sores. Even when using Aconite, it must be co-administered in large doses with Ginseng Radix et Rhizoma (Renshen) and Atractylodes Macrocephala Rhizome (Baizhu). How could it then mistakenly cause death? Regarding syndromes of wind-damp bi-syndrome with soreness and pain in the waist and feet, Coix Seed (Yiren), Poria (Fuling), Astragalus Root (Huangqi), and Euryale Seed (Qianshi) must be added for joint administration to ensure absolute safety.
Someone might ask: "Aconite is esteemed by the world, yet you abandon it to such an extent?" Aconite has indeed had its merits; my concern is that people mistakenly recognize it as a tonic and use it frequently. Wind-damp invading the Kidney is particularly difficult to treat. Retaining Aconite without deleting it is precisely to reserve its subtle applications. Otherwise, Stephania Tetrandra Root (Fangji) can also expel wind-damp within the Kidney. Keeping Fangji is acceptable, but why also retrieve Aconite? This is precisely because Aconite's efficacy surpasses that of Fangji, although its depletion of essence and blood is less severe than that of Fangji. Therefore, we keep Fangji and still keep Aconite. Generally speaking, Fangji treating wind-damp within the Kidney may only be used once to achieve a surprise effect, and should not be used again to cause harm. As for Aconite, it is permissible to use it once; regarding repeated use, it simply must not be used for a long duration.