防风，味甘、辛，气温，升也，阳也，无毒。系太阳本经之药，又通行脾、胃二经。古
人曾
分
上、中、下以疗病，其实，治风则一。盖随所用而听令，从各引经之药，无所不达，治一身
之痛
，疗半身之风，散上下之湿，祛阴阳之火，皆能取效。但散而不收，攻而不补，可暂时少用
以成功，而不可经年频用以助虚耳。
或问通圣散，专恃防风以散风邪，可常用乎？曰∶此方暂服尚不可，乌可常哉。盖防风
散人
真气，即以之散风邪，亦未可专恃也。
或问防风得黄 ，则不散邪而辅正，是防风亦可补之物，先生何谓攻而不补乎？夫黄
得防
风，而其功更大，未闻防风得黄 ，而其功更神，然则防风仍是攻而不补，非攻而亦补之物
也。近人皆以防风为散风神药，毋论外感与非外感俱用之，乃服而不效也。
或疑所用之不多也，更加分两，以致散尽真气，不可哂乎？殊不知防风宜于无风之时，
同黄
用之，可以杜邪风之不入于皮毛，非风邪已入而可用之物也。古人名一物，必在深意，顾
名而可悟矣。
防己，味辛、苦，气寒，阴也，无毒。能入肾以逐湿，腰以下至足湿热、足痛香港脚皆除，
利
大小二便，退膀胱积热，消痈散肿，除中风挛急，风寒湿疟热邪。似乎防己乃祛湿热行经之
圣药也，然其性只能下行，不能上达。凡湿热在上焦者，断不可用，用之则真气大耗，必至
危亡。说者谓防己乃下焦血分之药，可行于血分，而不可行于气分也。不知即是下焦湿热之
病
，只可一用，而亦不可再用。防己之气味尤悍，一服而湿热之在肾经者，立时解散。肾有补
而无泻，多服则泻肾矣，如之何可再用乎。
或问《本草》俱言通十二经，而吾子只言入肾，子不能无疑也。防己果通十二经，则上
焦头
目之病、胸膈咽喉之间，宜无不治之矣，何以只见其治腰以下之病而能愈耶？夫腰至于足，
正肾之所属，而谓非入肾者明验乎。然则言入十二经者，乃前人流传之误。而余说入肾者，
实有据之谈也。
或问防己治肾中之湿，与 治肾内之风，二者合之，不识可治肾乎？此其言似善，而
其祸
实大也。夫肾有补而无泻，用一缓泻，尚为不得已之治法。二者同施，肾将立惫矣。原因吾
子之问，以诫天下之人也。
或问防己利湿，不止在肾，而吾子独谓入肾，以为只能治腰足之湿也。然而，腰足之下，
不
尽属之肾，与腰相对者脐也；与足相附者，筋也。脐属脾而筋属肝，安在尽属于肾，而必谓
防己之治肾，而不治肝脾，人谁信之。故肾病，而脐与筋无不病矣。防己治肾中之湿，而脐
与筋中之湿尽消，非入肾而又入脾肝之谓也。防己入肾，不入肝脾，何必固疑乎。
防风，味甘、辛，气温，性升，属阳，无毒。它是太阳本经的药物，又能通行脾、胃二经。古人曾将其分为上、中、下三品来治疗疾病，其实，治疗风邪的作用是一样的。因为它随所配伍的药物而发挥作用，跟随各引经药，无处不到，治疗全身疼痛，治愈半身不遂之风，消散上下之湿气，祛除阴阳之火，都能取得疗效。但它只发散而不收敛，只攻伐而不补益，可以暂时少量使用以成功，但不可常年频繁使用以助长虚损。
有人问：通圣散专门依靠防风来疏散风邪，可以长期服用吗？回答说：这个方子暂时服用尚且不可以，何况长期服用呢？因为防风会耗散人的真气，即使用它来疏散风邪，也不应完全依赖它。
有人问：防风得到黄芪，就不再疏散邪气而是辅助正气，这说明防风也是能补益的药物，先生为什么说它只攻伐而不补益呢？黄芪得到防风，其功效更大，没听说过防风得到黄芪，其功效更神奇，那么防风仍然是只攻伐而不补益，不是既攻伐又补益的药物。近人都把防风当作疏散风邪的神药，不论外感还是非外感都使用它，结果服药无效。
有人怀疑使用的剂量不多，增加分量，以致耗散尽真气，这不是很可笑吗？殊不知防风适宜在无风之时，同黄芪一起使用，可以防止邪风侵入皮毛，而不是风邪已经侵入后可以使用药物。古人命名一物，必有深意，看着名字就可以领悟了。
防己，味辛、苦，气寒，属阴，无毒。能入肾以驱逐湿气，腰以下至足的湿热、足痛、香港脚（脚气病）都能消除，利大小便，退膀胱积热，消痈散肿，除中风挛急，风寒湿疟热邪。似乎防己是祛除湿热、通行经络的圣药，然而它的性质只能下行，不能上行。凡湿热在上焦者，绝对不可用，用了则真气大耗，必致危亡。评论的人说防己是下焦血分的药物，可以在血分运行，而不能在气分运行。不知道即使是下焦湿热的病，也只可一次使用，也不可再次使用。防己的气味尤其猛烈，一服下，湿热在肾经的，立即解散。肾有补而无泻，多服则泻肾了，怎么能再次使用呢？
有人问：《本草》都说通十二经，而你只说入肾，我不能不怀疑。防己果真通十二经，那么上焦头目之病、胸膈咽喉之间，应该没有治不好的了，为什么只见它能治好腰以下的病呢？腰部至于足部，正是肾所属的部位，这不是入肾的明证吗？然而说入十二经的，是前人流传的误传。而我说入肾的，是有实据的言论。
有人问：防己治疗肾中的湿，与附子治疗肾内的风，二者合用，不知是否可以治疗肾病？这话听起来似乎好，但其祸害实在大。肾有补而无泻，用一种缓泻的方法，尚且是不得已的治疗法。二者同时施用，肾将立刻衰竭了。我因为这个提问，来告诫天下的人。
有人问：防己利湿，不止在肾，而你独独说入肾，认为只能治疗腰足的湿。然而，腰足之下，并不全属于肾，与腰相对的肚脐；与足相连的是筋。肚脐属脾而筋属肝，怎么全属于肾，而必须说防己治肾，不治肝脾，谁会相信。所以肾病，肚脐和筋没有不病的。防己治疗肾中的湿，而肚脐和筋中的湿全部消除，并不是说入肾又入脾肝的意思。防己入肾，不入肝脾，何必固执地怀疑呢。
Fangfeng (Saposhnikoviae Radix), sweet and pungent in flavor, warm in nature, ascending and yang in property, non-toxic. It is a herb of the Taiyang (Greater Yang) channel, and also circulates through the Spleen and Stomach channels. Ancient practitioners once classified it into upper, middle, and lower categories for treating diseases; however, its function in treating wind remains the same. It follows the guidance of accompanying herbs, reaching everywhere, effective in treating pain throughout the body, hemiplegic wind, dispersing dampness above and below, and eliminating fire from yin and yang. However, it scatters without consolidating, attacks without tonifying. It can be used temporarily in small doses to achieve success, but should not be used frequently over years as it may exacerbate deficiency.
Someone asked: Tongsheng San relies specifically on Fangfeng to scatter wind pathogens; can it be taken regularly? The answer is: Even temporary use of this formula is inadvisable, let alone regular use. This is because Fangfeng dissipates true qi. Even when used to scatter wind pathogens, it should not be relied upon exclusively.
Someone asked: When combined with Huangqi (Astragali Radix), Fangfeng no longer scatters pathogens but supports healthy qi, suggesting that Fangfeng can also tonify. Why did you say it only attacks and does not tonify? When Huangqi is combined with Fangfeng, its efficacy increases, but there is no record of Fangfeng becoming more miraculous when combined with Huangqi. Therefore, Fangfeng remains an attacking rather than tonifying herb, not one that both attacks and tonifies. Recently, people regard Fangfeng as a divine herb for scattering wind, using it indiscriminately for both exogenous and non-exogenous conditions, resulting in ineffective treatment.
Some suspect that the dosage was too low; increasing the dose would dissipate all true qi, which would be ridiculous. In fact, Fangfeng is suitable for use together with Huangqi during periods without wind, to prevent pathogenic wind from invading the skin and hair, not for use after wind pathogens have already entered. The ancients named substances with deep meaning, which can be understood by looking at the name.
Fangji (Stephaniae Tetrandrae Radix), pungent and bitter in flavor, cold in nature, yin in property, non-toxic. It enters the Kidney to drive out dampness, eliminating damp-heat from the waist down to the feet, foot pain, and Hongjiaojiao (foot disease/gout), promoting urination, clearing accumulated heat in the Bladder, reducing abscesses and swelling, relieving convulsions due to wind-stroke, and treating wind-cold-dampness, malaria, and heat pathogens. It seems Fangji is a holy medicine for dispelling damp-heat and unblocking collaterals. However, its nature only descends and cannot ascend. For damp-heat in the Upper Jiao, it must absolutely not be used; doing so will severely deplete true qi, leading to critical danger. Commentators state that Fangji is a herb for the blood level of the Lower Jiao, capable of moving in the blood level but not the qi level. Even for damp-heat diseases in the Lower Jiao, it should be used only once and never again. The flavor and potency of Fangji are particularly fierce; a single dose instantly resolves damp-heat in the Kidney channel. The Kidney has functions of tonification but no purgation; excessive use purges the Kidney, so how can it be used repeatedly?
Someone asked: Bencao texts all state it enters the twelve channels, yet you only mention entering the Kidney. I cannot help but doubt. If Fangji truly enters the twelve channels, it should treat diseases of the head and eyes in the Upper Jiao, and the chest, diaphragm, and throat without exception. Why is it only seen to cure diseases below the waist? The waist down to the feet belongs precisely to the Kidney, which is clear evidence of its entry into the Kidney. Thus, the claim that it enters the twelve channels is a transmission error from predecessors. My statement that it enters the Kidney is based on solid evidence.
Someone asked: Fangji treats dampness in the Kidney, and Fuzi (Aconiti Lateralis Radix Preparata) treats wind in the Kidney; combining them, can they treat Kidney disease? This sounds good, but the harm is great. The Kidney has tonification but no purgation; even using a mild purgative is a method of last resort. Using both simultaneously will cause the Kidney to fail immediately. I raise this question to warn everyone.
Someone asked: Fangji promotes dampness removal not just in the Kidney, yet you insist it enters the Kidney, implying it only treats dampness in the waist and feet. However, below the waist and feet, not everything belongs to the Kidney; the navel corresponds to the waist, and tendons attach to the feet. The navel belongs to the Spleen, and tendons belong to the Liver. How can it all belong to the Kidney, and why must you say Fangji treats the Kidney but not the Liver and Spleen? Who would believe that? Therefore, if the Kidney is diseased, the navel and tendons are inevitably affected. Fangji treats dampness in the Kidney, and dampness in the navel and tendons is completely resolved; this does not mean it enters the Spleen and Liver as well. Fangji enters the Kidney, not the Liver or Spleen; why persist in doubt?