经云。壮火之气衰。少火之气壮。壮火食气。气食少火。壮火散气。少火生气。亢则害。承
乃制。制则生化。外列盛衰。害则败乱。生化大病。
火在丹田之下者。是为少火。少火则生气。离丹田而上者。是为壮火。壮火则食气。食气之
火。是为邪火。生气之火。是为真火。故少火亢极。则为壮火。夫五行之道。亢极则承。亢而过
甚。则害乎所胜。而承其下者。必从而制之。此天地自然之理也。六气虽属外因。而火气郁发。
未有不因诸内者。内经除亢则害一说。属诸六气胜复。余皆不离身中偏胜之机也。
丹溪云。火水木金土。各一其性。惟火有二。曰君火。人火也。曰相火。天火也。见于天者。
出于龙雷则木之气。出于海则水之气也。具于人者。寄于肝肾。肝属木而肾属水也。胆者肝之腑。
膀胱者肾之府。心包络者肾之配。三焦司肝肾之分。皆阴而属火也。天非此火不能生物。人非此
火不能有生。或曰。相火天火所同。何东垣谓为元气之贼。盖相火易
起。五性厥阳之火相煽则妄动矣。火起于妄。变化莫测。无时不有。煎熬真阴。阴虚则病。阴绝
则死。故曰。相火元气之贼。岐伯历举病机一十九条。而属火者五。原病式曰。诸风掉眩。皆属
于肝。火之动也。诸气 郁。皆属于肺。火之升也。诸湿肿满。皆属于脾。火之胜也。诸痛痒疮。
皆属于心。火之用也。是火皆出于脏腑者然也。按心为君火。而又有相火寄于肝肾。即内经所谓
一水不能胜二火也。五性之火。为物所感而动。即内经所谓一水不能胜五火也。又凡动皆属火。
故气郁火起于肺。大怒火起于肝。醉饱火起于脾。思虑火起于心。房劳火起于肾。此五脏所动之
火也。然而六腑皆然。如牙痛龈宣。腮颊颐肿。此胃火之所伤也。目黄口苦。坐卧不宁。此胆火
之所动也。舌苔喉痛。便秘不通。此大肠之火动也。癃闭淋沥。赤白带浊。此小肠之火动也。小
腹作痛。小便不利。此膀胱之火动也。头眩体倦。手足心热。此三焦之火动也。凡人一身。只阴
阳二气。阳气生发。阴气皆化为血。阳气不足。阴气皆化为火矣。阴虚火动者难治。如八味丸桂
附之类。虚火可补。如保元汤参 之类。实火可泻。如解毒汤三黄之类。郁火可发。如火郁汤升
柴之类。凡火盛者。不可骤用寒凉。必兼辛散。如泻阴火升阳汤、升阳散火汤之类。气壮脉实。
火盛颠狂者。可用硝、黄正治。如虚火盛而狂乱。以生姜汤从治之。若投以硝、黄正治。立危。
一切壮火狂阳痰气上冲膈膜。流入心包。诸药不效。内外热炽者。和剂紫雪可以平之。积热咽肿。
口舌生疮。烦躁妨闷。水浆不下。碧雪主之。好饵丹石。药毒迅发。壮热不已者。千金朴硝煎主
之。凡气有余便是火。气从左边起者。肝火也。佐金丸、当归龙荟丸。从脐下起者。阴火也。八
味丸、黑锡丹。五志过度。喜怒悲思不节。正气亢郁。变而为火者。于郁门求之。此治火之大略也。
赵养葵云。以火言之。有阳火。有阴火。有水中之火。有土中之火。有金中之火。有木中之
火。阳火者。天上太阳之火。生
于寅而死于酉。阴火者灯烛之火。生于酉而死于寅。此对待之火也。水中火者。霹雳火也。即龙
雷之火。无形而有声。得雨而益炽。见于季春而伏于季夏。原夫龙雷之见也。以五月一阴生。水
底冷。上天热。龙为阳物。故随阳而上升。冬至一阳来复。故龙亦随阳下伏。雷亦收声。人身肾
中相火。亦犹是也。以平日不能节欲。致命门火衰。肾中阴虚。龙火无藏身之位。故游于上而不
归。是以上焦烦热咳嗽等证。善治者以温肾之药。从其性而引之归源。行秋冬阳伏之令。而龙归
大海。此至理也。奈何今之治阴虚火者。以黄柏、知母为君。而愈寒其肾。益速其毙。良可悲哉。
若夫阴虚火旺者。此肾水干枯而火偏盛。宜补水以配火。亦不宜苦寒之品以灭火。壮水之主以制
阳光。正此谓也。如灯烛火。亦阴火也。须以膏油养之。不得杂一滴寒水。得水则灭矣。独有天
上火入于人身。如六气温热之病。及伤热中 之疾。可以凉水渥之。可以苦寒解之。其余炉中火
者。乃灰土中无焰之火。得木则烟。见湿则灭。须以灰培。实以温烬。人身脾土中火。以甘温养
其火而火自退。经曰。劳者温之。损者温之。甘能除大热。温能除大热。此之谓也。又空中之火。
附于木中。以常有坎水滋养。故火不外见。惟干柴生火燎原。可以止遏。力穷方止。人身肝火内
炽。郁闷烦躁。须以辛凉之品发达之。经曰。木郁达之。火郁发之。使之得遂其炎上之性。若以
寒药下之。则愈郁矣。热药投之。则愈炽矣。金中火者。凡山中金银之矿。或五金埋瘗之处。夜
必有光。此金郁土中而不得发越。故有光辉于外。人身皮毛窍中。自觉针刺蚊咬。及巅顶如火炎
者。此肺金气虚。火乘虚而现。肺主皮毛故也。东方木实。因西方金虚也。补北方之水。即所以
泻南方之火。虽曰治金中之火。而通治五行之火。无余蕴矣。脏腑虽皆有火。总不离于君相。盖
君火为阳火。可以直折。相火为龙火。仅可温顺。导之归源。又何患乎。今人率以知、柏治相火。
殊不知相火寄在肝肾之间。乃水中之
火。龙雷之火也。若用苦寒。则龙雷之火愈发矣。龙雷之火。每当浓阴骤雨之时。火焰愈炽。其
势诚不可遏。惟太阳一照。火自消灭。此得水则炽。得火则灭之一验也。惟八味丸桂附与火同气。
直入肾中。据其窟宅而招之。同气相求。相火安得不引之归源耶。且人身岂可一刻无火。譬之元
宵之鳌山走马灯。拜者舞者。飞者走者。无一不具。其中间惟是一火耳。火旺则动速。火微则动
缓。火熄则寂然不动。而拜舞飞走之躯壳。未尝不存也。是以老人以火为用。而少年惟恐多火。
高年惟恐无火。无火则运化艰而易衰。有火则精神健而难老。是火者老人性命之根。未可以水轻
折也。昔贤治喉干。谓八味丸为圣药。譬之釜底加薪。则釜中津气上腾。理则然矣。可见下虚者。
不但真阴虚。究竟真阳亦虚耳。命门之火。乃水中之火。相根据而永不相离也。火之有余。缘真水
之不足也。毫不敢去火。只补水以配火。壮水之主以制阳光。火之不足。因见水之有余也。亦不
必泻水。就于水中补火。益火之源以消阴翳。
〔诊〕石顽曰。按脉法云。浮而洪大为虚火。沉而实大为实火。其说似是而实纰缪。火性燔烈。
抑之则空。虽有虚实之分。绝无沉实之脉。详内经二火五火之说。无不本诸三焦。三焦配合心主。
代心司化育之令。即谓之君。而命门独操其权。故谓之相。若相火妄临五位。则为五志之火。其
实一气之亢。初无彼此。但以洪盛满指者为实火。或炎膈上。即为心肺之火。或迫中宫。即为脾
胃之火。或结下焦。即为小肠膀胱之火。分其部位以推之。随其微甚而调之。若弦细而数。按之
益坚。为少火气衰。而见肝肾真脉。非火使然。夫下焦之火。龙火也。水盛则蛰藏不见。其脉自
平。今弦细且数。乃冰雪阴凌之象。虚劳见此。最为剧候。或反虚大数疾。为食气之火。耗竭真
阴。虚阳飞越之兆。久病得此。百不一生。惟暴脱元气者。犹可峻补以敛固之。大抵火证之脉。
但有虚大。按之必空。断无实大之理。其火郁中焦。恶寒战
栗。则有六脉小匿者。此火气郁伏灰烬。不得发光舒焰。反兼寒水胜己之化矣。热结胃口。咳吐
结痰。亦有寸口滑实者。热遗下焦。淋浊溺痛。多有尺内洪滑者。皆胃中湿浊上逆下渗之候。终
与火无预也。当知火盛之脉。浮取虽洪盛滑疾。中按则软阔不坚。重按则豁然中空。寻之脉见指
傍。举指涩涩然如轻刀刮竹之状。方是无形之火象。若中宫有物阻碍。则关上屈曲而出。膈上有
痰凝滞。则寸口屈曲而上。总谓之钩。如无阻碍。则无屈曲之象矣。若洪盛而中按重按益实。指
下累累如循贯珠薏苡子状者。皆有形之湿热。蕴积于经脉之中。不当于火门求治也。
东垣治一人。伤寒目赤而烦渴。脉息七八至。按之不鼓击。经曰。脉至而从。按之不鼓。诸
阳皆然。此阴盛格阳于外。非热也。与姜、附之剂。汗出而愈。按此与海藏治狂言发斑。身热脉
沉细阴证例同。
丹溪治一妇。患心中如火烧。一烧便入小肠。急去小便。大便随时亦出。脉滑数。此相火送
入小肠。以四物加芩、连、 香、木通四剂。三年之患顿愈。
石顽治太史张弘蘧精气下脱。虚火上逆。怔忡失血证。诊其右关气口独显弦象。左尺稍嫌微
数。余皆微细搏指。明系阴火内伏之象。诊后。乃尊唯一详述病情。云自去冬劳心太过。精气滑
脱。加以怵惕恐惧。怔忡惊悸不宁。都门之医。峻用人参、桂、附。至岁底稍可。交春复剧如前。
遂乞假归吴。吴门诸医。咸效用参、附导火归源。固敛精气之药。略无一验。转觉委顿异常。稍
稍用心。则心系牵引掣痛。痛连脊骨对心处。或时痛引膺胁。或时巅顶如掀。或时臂股手足指甲
皆隐隐作痛。怔忡之状。如碓杵。如牵绳。如簸物。如绷绢。如以竹击空。控引头中。如失脑髓
之状。梦中尝自作文。觉时成篇可记。达旦倦怠睡去。便欲失精。精去则神魂如飞越之状。观其
气色鲜泽。言谈 。总属
真元下脱。虚阳上扰之候。细推脉证。始先虽属阳气虚脱。而过饵辛温峻补之剂。致阳暴亢而反
耗真阴。当此急宜转关以救垂绝之阴。庶可挽回前过。为疏二方。煎用保元合四君。丸用六味合
生脉。服及两月后。诸证稍平。但倦怠力微。因自检方书得补中益气汤为夏月当用之剂。于中加
入桂、附二味。一啜即喉痛声喑。复邀诊候。见其面颜精采。而声音忽喑。莫解其故。询之乃尊。
知为升、柴、桂、附升动虚阳所致。即以前方倍生脉服之。半月后。声音渐复。日渐向安。但起
居调摄。殊费周折。衣被过暖。便咽干痰结。稍凉则背微畏寒。或啜热饮。则周身大汗。怔忡走
精。此皆宿昔过用桂、附。余热内伏而寻出路也。适有石门董载臣。谓其伏火未清。非芩、连不
能解散。时值嘉平。不敢轻用苦寒。仲春载臣复至。坐俟进药。可保万全。服数剂。形神爽朗。
是后坚心服之。至初夏。反觉精神散乱。气不收摄。乃尽出从前所服之方。就正于予。予谓桂、
附阳药。火毒之性。力能上升。得参以濡之。故可久伏下焦。与龙潜水底不异。若究其源。惟滋
肾丸一方。为之正治。但既经芩、连折之于上。岂堪复受知、柏侵伐于下乎。从头打算。自春徂
夏。不离苦寒。苦先入心。必从火化。何敢兼用肉桂引动虚阳。发其潜伏之性哉。端本澄源。仍
不出六味合生脉。经岁常服。不特壮水制阳。兼得金水相生之妙用。何惮桂、附之余毒不化耶。
《黄帝内经》说：壮火（亢盛的阳气）会使正气衰弱，少火（温和的阳气）会使正气强盛。壮火会消耗正气，正气依赖少火而充养；壮火会散失正气，少火能滋生正气。阳气亢盛会为害，有制约才能平衡，有制约才能生化万物，外在表现出盛衰的变化。为害则导致败乱，生化失常则产生大病。
火位于丹田之下，称为少火，少火能滋生元气。火离丹田而上行，称为壮火，壮火会消耗元气。消耗元气的火，称为邪火；滋生元气的火，称为真火。所以少火亢盛到极点，就转化为壮火。五行的规律是，亢盛到极点就会有制约。如果亢盛过度，就会伤害它所克制的脏腑，而处于下方的脏腑必然会对它进行制约。这是天地自然的道理。六气虽然属于外因，但火气的郁结发作，没有不是由内部因素引起的。《内经》除了“亢则害”这一说法属于六气胜复的理论外，其余都不离开身体内部偏胜的机理。
朱丹溪说：水、火、木、金、土，各自具有不同的本性，只有火有两种：一种是君火，即人火；另一种是相火，即天火。表现在自然界中的，出于龙雷之气的是木的气，出于大海的是水的气。体现在人身上的，寄居于肝肾。肝属木，肾属水。胆是肝的腑，膀胱是肾的府，心包络是肾的配合，三焦主管肝肾的分野，这些都是阴体而属于火的功能。自然界没有这种火就不能化生万物，人没有这种火就不能维持生命。有人说，相火和天火是相同的，为什么李东垣称它为元气的贼？大概是因为相火容易兴起，当五种情志引发的厥阳之火相互煽动时，就会妄动。火起于妄动，变化莫测，无时不在，煎熬真阴，阴虚就会生病，阴绝就会死亡。所以说，相火是元气的贼。岐伯列举了病机十九条，其中属于火的有五条。刘完素在《原病式》中说：各种风病震颤眩晕，都归属于肝，这是火在动摇；各种气机郁滞，都归属于肺，这是火在上升；各种湿病肿胀满闷，都归属于脾，这是火在胜复；各种疼痛瘙痒疮疡，都归属于心，这是火的作用。这些火都是出于脏腑的。按心为君火，同时又有相火寄居在肝肾，这就是《内经》所说的“一水不能胜二火”。五种情志之火，因外物刺激而动，这就是《内经》所说的“一水不能胜五火”。凡是动的都属于火，所以气郁火起于肺，大怒火起于肝，醉饱火起于脾，思虑火起于心，房劳火起于肾。这是五脏所动的火。然而六腑也是如此，如牙痛牙龈宣露，腮颊颐部肿胀，这是胃火所伤；目黄口苦，坐卧不宁，这是胆火所动；舌苔喉痛，便秘不通，这是大肠之火动；癃闭淋沥，赤白带浊，这是小肠之火动；小腹作痛，小便不利，这是膀胱之火动；头眩体倦，手足心热，这是三焦之火动。凡人一身，只有阴阳二气，阳气生发，阴气都化为血。如果阳气不足，阴气都会化为火。阴虚火动者难治。如八味丸、桂枝、附子之类，用于虚火可补益；如保元汤、人参之类，用于实火可泻除；如解毒汤、黄连、黄芩、大黄之类，用于郁火可发散；如火郁汤、升麻、柴胡之类。凡火势旺盛者，不可骤然使用寒凉药，必须兼用辛散药，如泻阴火升阳汤、升阳散火汤之类。如果气壮脉实，火盛导致颠狂，可以用芒硝、大黄正治。如果是虚火盛而导致狂乱，用生姜汤从治。如果投以芒硝、大黄正治，立即会有危险。一切壮火狂阳、痰气上冲膈膜、流入心包，诸药无效的，内外热炽盛的，可用和剂紫雪来平抑。积热咽肿，口舌生疮，烦躁胸闷，水浆不下，用碧雪主治。喜好服用丹石药物，药毒迅速发作，壮热不止的，用千金朴硝煎主治。凡是气有余便是火。气从左边起的，是肝火，用佐金丸、当归龙荟丸治疗；从脐下起的，是阴火，用八味丸、黑锡丹治疗。五志过度，喜怒悲思不节制，正气亢盛郁结，变而为火的，在郁证门中求治。这是治火的大略。
赵献可说：就火而言，有阳火，有阴火，有水中之火，有土中之火，有金中之火，有木中之火。阳火，就是天上的太阳之火，生于寅时而死于酉时。阴火，就是灯烛之火，生于酉时而死于寅时。这是对立的火。水中的火，就是霹雳火，也就是龙雷之火，无形而有声，遇雨反而更旺，见于季春而伏于季夏。起初龙雷的出现，是因为五月一阴生，水底冷，上天热，龙为阳物，所以随阳而上升。冬至一阳来复，所以龙也随阳下伏，雷也收声。人身肾中的相火，也是这样。因为平日不能节制欲望，导致命门火衰，肾中阴虚，龙火没有藏身的位置，所以游于上而不归。因此出现上焦烦热咳嗽等证。善于治疗的，用温肾的药，顺从其性而引导它回归本源，实行秋冬阳气潜伏的命令，使龙归大海。这是至理。奈何现在治疗阴虚火的人，把黄柏、知母作为主药，反而使肾更寒，加速死亡，实在可悲。如果是阴虚火旺，这是肾水干枯而火偏盛，宜补水以配火，也不宜用苦寒之品灭火。“壮水之主，以制阳光”，说的就是这个意思。如灯烛火，也是阴火，需要用膏油滋养，不得混杂一滴寒水，得水就灭了。只有天上的火进入人身，如六气温热之病，及伤热中暑之疾，可以用凉水浇灌，可以用苦寒解除。其余炉中的火，是灰土中无焰的火，得木则烟，见湿则灭，需要用灰培护，实以温烬。人身脾土中的火，用甘温养其火而火自退。《内经》说：劳者温之，损者温之。甘能除大热，温能除大热，说的就是这个意思。还有空中之火，附着在木中，因为有坎水滋养，所以火不外现。只有干柴生火燎原，可以止遏，力穷才停止。人身肝火内炽，郁闷烦躁，需要用辛凉的药品发散它。《内经》说：木郁达之，火郁发之，使其得以顺应炎上的本性。如果用寒药下之，则更加郁结。用热药投之，则更加炽盛。金中之火，凡是山中金银矿藏，或五金埋藏之处，夜晚必有光，这是金郁在土中而不能发越，所以有光辉在外。人身皮毛孔窍中，自觉针刺蚊咬，及头顶如火烧者，这是肺金气虚，火乘虚而现，因为肺主皮毛。东方木实，是因为西方金虚。补北方之水，就是泻南方之火。虽然说是治金中之火，而通治五行之火，没有遗漏了。脏腑虽都有火，总不离于君火和相火。盖君火为阳火，可以直接折服；相火为龙火，只能温顺，引导它回归本源。又有什么可担心的呢？现在的人都用知母、黄柏治疗相火，却不知道相火寄居在肝肾之间，是水中之火，龙雷之火。如果用苦寒药，则龙雷之火越发猛烈。龙雷之火，每当浓阴骤雨之时，火焰更炽盛，其势确实不可遏制。只有太阳一照，火自然消灭。这是得水则炽，得火则灭的一个验证。只有八味丸中的桂枝、附子与火同气，直入肾中，占据其巢穴而招引它，同气相求，相火怎么能不引导它回归本源呢？况且人身哪能一刻没有火？譬如元宵节的鳌山走马灯，拜者舞者，飞者走者，无一不具备，其中间只有一团火罢了。火旺则动得快，火微则动得慢，火熄则寂静不动，而拜舞飞走的躯壳，未尝不存在。所以老人以火为用，而少年惟恐多火。高年惟恐无火，无火则运化艰难而易衰老，有火则精神健旺而难老。这火是老人性命的根本，不可以用水轻易折服。昔日贤人治疗喉干，谓八味丸为圣药，譬如釜底加薪，则釜中津气上腾，道理就是这样。可见下虚者，不但真阴虚，究竟真阳也虚。命门之火，是水中之火，与水相伴而永不相离。火有余，缘于真水不足，丝毫不敢去火，只补水以配火，“壮水之主，以制阳光”。火不足，因见水有余，也不必泻水，就在补水中补火，“益火之源，以消阴翳”。
【诊法】罗美（字石顽）说：按脉法说，浮而洪大为虚火，沉而实大为实火。这种说法似是而非，其实谬误。火性燔烈，抑制它则空虚，虽然有虚实之分，绝无沉实的脉象。详细考察《内经》二火五火的说法，无不本源于三焦。三焦配合心主，代心司化育之令，这就叫君，而命门独操其权，所以叫相。如果相火妄临五位，就成为五志之火，其实是一气的亢盛，初无彼此之分，只是以洪盛满指者为实火，或者炎于膈上，就是心肺之火；或者迫于中宫，就是脾胃之火；或者结于下焦，就是小肠膀胱之火。分其部位来推究，随其轻重来调治。如果脉弦细而数，按之更坚，是少火气衰，而出现肝肾的真脏脉，不是火造成的。下焦之火，是龙火，水盛则蛰藏不见，其脉自然平和。现在脉弦细且数，乃是冰雪阴凌之象，虚劳见此，最为危重之候。或者反见虚大数疾，是食气之火，耗竭真阴，虚阳飞越的征兆。久病得此，百无一活。只有暴脱元气者，还可以峻补以敛固之。大抵火证的脉，但有虚大，按之必空，断无实大的道理。其火郁在中焦，恶寒战栗，则有六脉小匿者，这是火气郁伏在灰烬中，不得发光舒焰，反而兼有寒水胜己的化象。热结胃口，咳吐结痰，也有寸口滑实的。热遗下焦，淋浊溺痛，多有尺内洪滑的，这都是胃中湿浊上逆下渗的征候，最终与火无关。应当知道火盛的脉，浮取虽洪盛滑疾，中按则软阔不坚，重按则豁然中空，寻之脉见指旁，举指涩涩然如轻刀刮竹之状，这才是无形之火象。如果中宫有物阻碍，则关上屈曲而出；膈上有痰凝滞，则寸口屈曲而上，总称之为钩。如果没有阻碍，则无屈曲之象。如果洪盛而中按重按益实，指下累累如循贯珠薏苡子状者，都是有形的湿热，蕴积于经脉之中，不应当在火门求治。
李东垣治疗一人，患伤寒目赤而烦渴，脉息七八至，按之不鼓击。《内经》说：脉至而从，按之不鼓，诸阳皆然。这是阴盛格阳于外，非热也。给予姜、附之剂，汗出而愈。按此与海藏治疗狂言发斑，身热脉沉细阴证例相同。
朱丹溪治疗一妇人，患心中如火烧，一烧便入小肠，急去小便，大便随时亦出，脉滑数。这是相火送入小肠，用四物汤加黄芩、黄连、木香、木通，四剂后，三年之患顿愈。
罗美治疗太史张弘蘧精气下脱，虚火上逆，怔忡失血证。诊其右关气口独显弦象，左尺稍嫌微数，余皆微细搏指。明系阴火内伏之象。诊后，其父唯一详述病情，说自去年冬天劳心太过，精气滑脱，加上怵惕恐惧，怔忡惊悸不宁。都城的医生，峻用人参、桂枝、附子，到岁末稍可，交春复发剧烈如前。于是乞假回吴地。吴地的各位医生，都效用参、附导火归源，固敛精气之药，略无一验，转觉委顿异常。稍稍用心，则心系牵引掣痛，痛连脊骨对心处，或时痛引膺胁，或时巅顶如掀，或时臂股手足指甲皆隐隐作痛。怔忡之状，如碓杵，如牵绳，如簸物，如绷绢，如以竹击空，控引头中，如失脑髓之状。梦中常自作文，觉时成篇可记，达旦倦怠睡去，便欲失精。精去则神魂如飞越之状。观其气色鲜泽，言谈... 总属真元下脱，虚阳上扰之候。细推脉证，始先虽属阳气虚脱，而过饵辛温峻补之剂，致阳暴亢而反耗真阴。当此急宜转关以救垂绝之阴，庶可挽回前过。为其开具两方，煎用保元汤合四君子汤，丸用六味地黄丸合生脉散。服及两月后，诸证稍平，但倦怠力微。因自检方书得补中益气汤为夏月当用之剂，于中加入桂枝、附子二味，一喝即喉痛声喑。再次邀请诊候，见其面颜精采，而声音忽喑，莫解其故。询问其父，知为升麻、柴胡、桂枝、附子升动虚阳所致。即用以前方倍加生脉散服用。半月后，声音渐复，日渐向安。但起居调摄，殊费周折。衣被过暖，便咽干痰结；稍凉则背微畏寒；或啜热饮，则周身大汗，怔忡走精。此皆宿昔过用桂枝、附子，余热内伏而寻出路也。适有石门董载臣，谓其伏火未清，非黄芩、黄连不能解散。时值嘉平（十二月），不敢轻用苦寒。仲春载臣复至，坐俟进药，可保万全。服数剂，形神爽朗。是后坚心服之，至初夏，反觉精神散乱，气不收摄。乃尽出从前所服之方，就正于我。我说桂枝、附子是阳药，火毒之性，力能上升，得人参以濡润之，故可久伏下焦，与龙潜水底不异。若究其源，惟有滋肾丸一方，为之正治。但既经黄芩、黄连折之于上，岂堪复受知母、黄柏侵伐于下乎？从头打算，自春徂夏，不离苦寒。苦先入心，必从火化，何敢兼用肉桂引动虚阳，发其潜伏之性哉？端本澄源，仍不出六味地黄丸合生脉散。经岁常服，不特壮水制阳，兼得金水相生之妙用，何惮桂枝、附子的余毒不化耶？
The *Yellow Emperor's Inner Canon* states: Vigorous fire (excessive Yang qi) causes the decline of healthy qi, while mild fire (gentle Yang qi) strengthens healthy qi. Vigorous fire consumes qi, whereas qi nourishes itself through mild fire; vigorous fire scatters qi, while mild fire generates qi. When Yang qi reaches an extreme of hyperactivity, it becomes harmful; only when there is restraint can balance be achieved, and only with restraint can transformation and generation occur, manifesting externally as prosperity or decline. Harm leads to disorder, and dysfunction in transformation and generation results in severe disease.
Fire located below the Dantian is called mild fire; mild fire generates Yuan Qi (Primordial Qi). Fire rising away from the Dantian is called vigorous fire; vigorous fire consumes qi. The fire that consumes qi is termed evil fire (Pathogenic Fire), while the fire that generates qi is termed true fire (True Fire). Therefore, when mild fire reaches its peak of hyperactivity, it transforms into vigorous fire. The principle of the Five Elements dictates that when hyperactivity reaches its limit, there must be restraint. If hyperactivity is excessive, it harms the element it overcomes, and the element below will inevitably exert control over it. This is the natural law of heaven and earth. Although the Six Qi (Six Pathogenic Factors) belong to external causes, the stagnation and eruption of fire qi invariably stem from internal factors. Apart from the concept of "hyperactivity leads to harm" belonging to the theory of excess and counteraction of the Six Qi, the rest do not depart from the mechanism of internal imbalance within the body.
Zhu Danxi stated: Water, fire, wood, metal, and earth each possess distinct natures, but fire has two types: one is Ministerial Fire (Jun Huo), which is human fire; the other is Assistant Fire (Xiang Huo), which is heavenly fire. Manifested in nature, that arising from dragon-thunder energy pertains to wood qi, and that arising from the sea pertains to water qi. In humans, it resides in the Liver and Kidney. The Liver belongs to Wood, and the Kidney belongs to Water. The Gallbladder is the paired organ of the Liver, the Bladder is the mansion of the Kidney, the Pericardium is the counterpart of the Kidney, and the San Jiao (Triple Burner) governs the domains of the Liver and Kidney. All these are Yin structures yet functionally associated with Fire. Without this heavenly fire, nature cannot generate all things; without this human fire, life cannot be sustained. Some ask: Since Assistant Fire and Heavenly Fire are the same, why does Li Dongyuan call it a thief of Yuan Qi? It is likely because Assistant Fire easily arises; when the Jue-Yang (Rebellious Yang) fires of the five emotions fan each other, they move recklessly. Fire arises from reckless movement, changes unpredictably, exists at all times, and fries True Yin. Yin deficiency leads to disease, and Yin exhaustion leads to death. Thus, it is said that Assistant Fire is a thief of Yuan Qi. Qibo listed nineteen pathogenesis clauses, five of which relate to fire. Liu Wansu wrote in *Yuan Bing Shi*: "All wind diseases involving tremors and dizziness belong to the Liver," indicating fire in motion; "All qi disorders involving depression belong to the Lung," indicating fire rising; "All dampness diseases involving swelling and fullness belong to the Spleen," indicating fire overcoming; "All pain, itching, and sores belong to the Heart," indicating the function of fire. These fires all originate from the Zang-Fu organs. The Heart is Ministerial Fire, while Assistant Fire resides in the Liver and Kidney; this corresponds to the *Inner Canon*'s statement that "one water cannot overcome two fires." The fires of the five emotions move due to external stimuli, corresponding to the *Inner Canon*'s statement that "one water cannot overcome five fires." Generally, all movement belongs to fire. Thus, qi depression generates fire in the Lung; anger generates fire in the Liver; drunkenness and overeating generate fire in the Spleen; overthinking generates fire in the Heart; sexual exhaustion generates fire in the Kidney. These are the fires moved by the five Zang organs. However, the six Fu organs are similar: toothache and receding gums, swelling of the cheeks and jaw, are injuries from Stomach fire; yellow eyes and bitter taste, restlessness in sitting and lying, are movements of Gallbladder fire; tongue coating, sore throat, constipation, are movements of Large Intestine fire; strangury and dribbling, red and white turbid discharge, are movements of Small Intestine fire; lower abdominal pain and difficult urination, are movements of Bladder fire; dizziness, fatigue, and heat in the palms and soles, are movements of San Jiao fire. The human body possesses only Yin and Yang qi. When Yang qi generates, Yin qi transforms into blood. If Yang qi is insufficient, Yin qi transforms into fire. Cases of Yin deficiency with fire movement are difficult to treat. For example, Ba Wei Wan (Eight-Ingredient Pill), Gui Zhi Tang (Cinnamon Twig Decoction), and Fu Zi (Aconite Root) are used to tonify deficient fire. Bao Yuan Tang (Preserve Qi Decoction) and Ren Shen (Ginseng Radix et Rhizoma) are used to drain excess fire. Jie Du Tang (Detoxification Decoction) and Huang Qin (Scutellariae Radix), Huang Lian (Coptidis Rhizoma), Da Huang (Rhei Radix et Rhizoma) are used to vent depressed fire. Huo Yu Tang (Fire-Stagnation Decoction) and Sheng Ma (Cimicifugae Rhizoma), Chai Hu (Bupleuri Radix) are also used. When fire is abundant, cold and cooling herbs should not be used abruptly; acrid and dispersing herbs must be combined, such as Xie Yin Huo Sheng Yang Tang (Drain Yin Fire and Raise Yang Decoction) and Sheng Yang San Huo Tang (Raise Yang and Scatter Fire Decoction). If qi is robust and the pulse is solid, and fire abundance causes mania, Mang Xiao (Natrii Sulfas) and Da Huang can be used for direct treatment. If deficient fire abundance causes mania, Sheng Jiang Tang (Fresh Ginger Decoction) should be used for indirect treatment. Using Mang Xiao and Da Huang directly in cases of deficient fire would lead to immediate danger. For all cases of vigorous fire, manic Yang, phlegm-Qi rushing upward to the diaphragm, flowing into the Pericardium, where various medicines fail, and with intense internal and external heat, He Ji Zi Xue (Purple Snow from the Formulary Office) can pacify it. For accumulated heat causing swollen throat, mouth and tongue ulcers, irritability, chest oppression, and inability to swallow liquids, Bi Xue (Green Snow) is indicated. For those who habitually take cinnabar and sulfur, leading to rapid onset of drug toxicity and persistent high fever, Qian Jin Piao Xiao Jian (Thousand-Gold Magnolia Bark Decoction) is indicated. Generally, excess Qi constitutes fire. Qi rising from the left indicates Liver fire, treated with Zuo Jin Wan (Assist Metal Pill) and Dang Gui Long Hui Wan (Angelica Dragon Bile Pill). Qi rising from below the umbilicus indicates Yin fire, treated with Ba Wei Wan and Hei Xi Dan (Black Tin Pill). Excesses of the five emotions, unregulated joy, anger, sorrow, and thought, cause Zheng Qi (Upright Qi) to become hyperactive and stagnant, transforming into fire; these are sought in the chapter on stagnation. This is the general approach to treating fire.
Zhao Yangkui stated: Regarding fire, there is Yang fire and Yin fire, fire in water, fire in earth, fire in metal, and fire in wood. Yang fire is the sun's fire in the sky, born at Yin hour and dying at You hour. Yin fire is the fire of lamps and candles, born at You hour and dying at Yin hour. These are opposing fires. Fire in water is thunderbolt fire, i.e., dragon-thunder fire, formless but audible, intensifying with rain, appearing in late spring and hiding in late summer. Initially, the appearance of dragon-thunder is because in the fifth month, one Yin emerges; the water bottom is cold, the sky is hot. Dragons are Yang entities, so they rise with Yang. At Winter Solstice, one Yang returns, so dragons submerge with Yang, and thunder silences. The Assistant Fire in the human Kidney is the same. Due to lack of desire regulation in daily life, Ming Men (Gate of Life) fire declines, Kidney Yin becomes deficient, and dragon-fire has no place to hide, thus wandering upward and not returning. Hence, symptoms like upper Jiao irritability, heat, and cough appear. Skilled practitioners use Kidney-warming herbs to follow its nature and guide it back to the source, implementing the command of winter Yang submergence, so the dragon returns to the sea. This is the profound truth. Alas, nowadays, those treating Yin-deficient fire make Huang Bo (Phellodendri Cortex) and Zhi Mu (Anemarrhenae Rhizoma) their chief drugs, further chilling the Kidney and hastening death. How tragic! If it is Yin deficiency with fire hyperactivity, this means Kidney water is dried up and fire is relatively strong. One should tonify water to match fire, rather than using bitter-cold substances to extinguish fire. "Strengthen the master of water to control sunlight" refers to this. Like lamp-fire, it is also Yin fire, requiring oil to nourish it; not a drop of cold water should be mixed, or it will be extinguished. Only heavenly fire entering the human body, such as diseases of the Six Qi warm-heat pathogens, or heat-stroke, can be cooled with cold water or resolved with bitter-cold herbs. Other fires in the furnace are flameless fires in ash and soil; they smoke when meeting wood and extinguish when meeting moisture. They require ash protection and warmth to sustain. The fire in the human Spleen Earth is best treated by nourishing it with sweet-warm herbs, after which the fire naturally retreats. The *Canon* says: "For exhaustion, use warmth; for damage, use warmth." Sweetness can remove great heat, and warmth can remove great heat; this is what is meant. There is also fire in the air, attached to wood, nourished by Kan Water, so it does not appear externally. Only dry wood catching fire and spreading can be stopped when strength fails. Internal blazing of Liver fire, causing depression and irritability, requires acrid-cool herbs to disperse it. The *Canon* says: "For wood stagnation, achieve dispersion; for fire stagnation, vent it," allowing it to follow its flaming-upward nature. Using cold purgatives increases stagnation; using hot herbs increases intensity. Fire in metal: mines of gold and silver or buried metals often glow at night. This is metal stagnating in earth unable to emerge, hence shining externally. Sensations of needle-pricks or mosquito bites in skin pores, or burning in the vertex, indicate Lung Metal Qi deficiency with fire exploiting the void, as the Lung governs skin and hair. Eastern Wood is substantial because Western Metal is deficient. Tonifying Northern Water is equivalent to draining Southern Fire. Although described as treating fire in metal, it comprehensively treats fire in the Five Elements without omission. Although all Zang-Fu have fire, it ultimately revolves around Ministerial and Assistant fire. Ministerial fire is Yang fire, which can be directly subdued; Assistant fire is dragon-fire, which can only be gently guided back to the source. Why worry? Nowadays, people indiscriminately use Zhi Mu and Huang Bo to treat Assistant fire, not knowing it resides between the Liver and Kidney, being fire in water, dragon-thunder fire. Using bitter-cold herbs makes dragon-thunder fire flare more fiercely. During heavy clouds and sudden rain, dragon-thunder fire burns even hotter, unstoppable. Only when the sun shines does the fire vanish. This proves that meeting water intensifies it, while meeting fire extinguishes it. Only Gui Zhi and Fu Zi in Ba Wei Wan share the same nature as fire, entering the Kidney directly, occupying its lair to attract it. Following the principle of similar energies attracting, how can Assistant fire not be guided back to the source? Moreover, how can the human body exist without fire for a moment? Consider the lanterns of the Lantern Festival: bowers, dancers, flyers, walkers—all present, driven by a single fire within. Strong fire moves fast, weak fire moves slow, extinguished fire remains still, yet the bodies remain. Thus, the elderly rely on fire, while the young fear too much fire. The elderly fear having no fire; without fire, transformation is difficult and aging is easy; with fire, spirit is robust and aging is slow. This fire is the root of life for the elderly and should not be lightly suppressed by water. Ancient sages treated dry throat with Ba Wei Wan as a sacred medicine, likening it to adding fuel to the pot so steam rises. The logic holds. Thus, lower deficiency involves not only True Yin deficiency but also True Yang deficiency. Ming Men fire is fire in water, inseparable from water. Excess fire stems from insufficient True Water; dare not eliminate fire, only tonify water to match fire, "strengthen the master of water to control sunlight." Insufficient fire stems from excess water; dare not drain water, only tonify fire within water, "benefit the source of fire to dissipate Yin shadows."
[Diagnosis] Luo Mei (style name Shiwan) stated: Pulse methods say: floating, surging, large pulses indicate deficient fire; deep, solid, large pulses indicate excess fire. This view seems plausible but is actually erroneous. Fire nature is blazing; when suppressed, it becomes empty. Although there is a distinction between deficiency and excess, there is absolutely no deep-solid pulse. Examining the *Inner Canon*'s discussion of two fires and five fires, all originate from the San Jiao. The San Jiao pairs with the Heart Master, acting on behalf of the Heart to manage transformation and generation, thus called Minister, while the Ming Men holds sole authority, thus called Assistant. If Assistant fire recklessly occupies the five positions, it becomes fire of the five emotions. Essentially, it is the hyperactivity of one Qi, with no distinction between self and other. Simply put, surging and filling the fingers indicates excess fire. If blazing above the diaphragm, it is Heart-Lung fire; if pressing the middle Jiao, it is Spleen-Stomach fire; if knotting in the lower Jiao, it is Small Intestine-Bladder fire. Analyze by location and regulate according to severity. If the pulse is wiry, thin, and rapid, becoming harder upon pressure, it indicates declining mild fire and the appearance of true Liver-Kidney pulses, not caused by fire. Lower Jiao fire is dragon-fire; when water is abundant, it hibernates unseen, and the pulse is peaceful. Now, wiry, thin, and rapid pulses indicate ice-like Yin oppression. In consumptive diseases, this is a critical sign. Alternatively, a deficient, large, rapid, and frantic pulse indicates fire consuming Qi, exhausting True Yin, and flying away of deficient Yang. In chronic illness, this portends death in nearly all cases. Only in acute collapse of Yuan Qi can drastic tonification consolidate it. Generally, fire syndrome pulses are deficient and large, empty upon pressure, never truly large and solid. When fire stagnates in the Middle Jiao, causing aversion to cold and shivering, the six pulses may be small and hidden. This is fire qi stagnating in ashes, unable to shine or flare, mimicking the transformation of conquering Cold-Water. Heat knotting at the stomach opening, causing coughing up of phlegm, may show slippery and solid pulses at the Cun position. Heat lingering in the lower Jiao, causing strangury and painful urination, often shows surging and slippery pulses at the Chi position. These are signs of damp-turbidity in the Stomach reversing upward and seeping downward, unrelated to fire. One must know that fire-surplus pulses, though surging, slippery, and rapid upon superficial palpation, become soft and broad without firmness upon moderate pressure, and hollow upon deep pressure. Seeking the pulse reveals it at the finger sides; lifting the finger feels rough like scraping bamboo with a light knife. This is the image of formless fire. If obstruction exists in the Middle Jiao, the Guan pulse curves outwards; if phlegm stagnates above the diaphragm, the Cun pulse curves upwards. Both are called "hook" pulses. Without obstruction, there is no curving. If surging, and deeper pressure makes it more solid, feeling like rolling pearls or coix seeds under the fingers, these are有形 (form-bound) damp-heat accumulating in meridians, not to be treated in the fire category.
Li Dongyuan treated a patient with typhoid presenting with red eyes, irritability, and thirst. The pulse was seven to eight beats per breath, but did not thump upon pressure. The *Canon* states: "Pulse follows but does not thump upon pressure; this applies to all Yang conditions." This indicates Yin excess repelling Yang outward, not heat. He administered ginger and aconite preparations, and recovery followed sweating. This case aligns with Hai Zang's treatment of delirium and macules with body heat and deep-thin Yin-type pulses.
Zhu Danxi treated a woman suffering from heartburn like fire, radiating to the Small Intestine, causing urgent urination and simultaneous defecation. Her pulse was slippery and rapid. This was Assistant fire transmitting to the Small Intestine. He prescribed Si Wu Tang (Four Substances Decoction) plus Huang Qin, Huang Lian, Mu Xiang, and Mu Tong for four doses, curing a three-year ailment instantly.
Luo Mei treated Grand Secretary Zhang Hongqu, who suffered from descending Jing Essence, rebellious deficient fire, palpitations, and hemoptysis. Palpating his Right Guan Qi Kou revealed a wiry image, while the Left Chi was slightly micro-rapid; the rest were micro-thin and beating against the finger. This clearly indicated latent Yin fire. After diagnosis, his father detailed the history: excessive mental labor last winter caused essence slipping, compounded by fright and fear, leading to restless palpitations. Doctors in the capital used drastic doses of Ren Shen, Gui Zhi, and Fu Zi. Symptoms improved slightly by year-end but worsened severely in spring. He returned to Wu. Doctors in Wu all used Ren Shen and Fu Zi to guide fire back to the source and consolidate essence, with no effect, leading to extreme prostration. Mental effort triggered pulling pain in the Heart system, radiating to the spine opposite the heart, or to the chest and ribs, or vertigo, or dull pain in arms, thighs, fingers, and nails. Palpitations felt like pestle pounding, rope pulling, winnowing, stretching silk, or striking bamboo hollowly, controlling the head as if losing brain marrow. He dreamed of writing essays, waking to find them complete. Exhaustion led to sleep and seminal emission; loss of essence made the soul feel like flying away. His complexion was lustrous, speech coherent. Overall, it was True Yuan descending and deficient Yang disturbing upward. Careful analysis showed initial Yang Qi collapse, but excessive pungent-warm drastic tonification caused violent Yang hyperactivity, consuming True Yin. Urgently, the course needed changing to save the nearly extinct Yin. Two prescriptions were given: decoction of Bao Yuan Tang combined with Si Jun Zi Tang (Four Gentlemen Decoction); pills of Liu Wei Di Huang Wan (Six-Ingredient Pill with Rehmannia) combined with Sheng Mai San (Generate the Pulse Powder). After two months, symptoms stabilized, but fatigue persisted. Checking medical books, he found Bu Zhong Yi Qi Tang (Tonify the Middle and Augment the Qi Decoction) suitable for summer, adding Gui Zhi and Fu Zi. One dose caused sore throat and hoarseness. Re-examination showed bright complexion but sudden hoarseness. Inquiry revealed Sheng Ma, Chai Hu, Gui Zhi, and Fu Zi had raised deficient Yang. He resumed the previous formula with doubled Sheng Mai San. After half a month, voice recovered, health improved. However, lifestyle management was difficult. Over-warming caused dry throat and phlegm knots; slight cooling caused mild back chills; drinking hot drinks caused profuse sweating, palpitations, and seminal leakage. These resulted from past overuse of Gui Zhi and Fu Zi, leaving residual heat seeking an exit. Dong Zaichen from Shimen noted latent fire remained, requiring Huang Qin and Huang Lian to resolve. In December, bitter-cold herbs were avoided. In mid-spring, Dong arrived, waiting for medication assurance. After several doses, spirit and shape became clear. He persisted, but by early summer, spirit scattered, Qi unrestrained. He presented all previous formulas to me. I stated that Gui Zhi and Fu Zi are Yang drugs with fire-toxic properties, rising powerfully. Combined with Ren Shen to moisten, they linger in the lower Jiao like dragons diving. Investigating the source, Zi Shui Wan (Nourish Water Pill) is the correct treatment. But since Huang Qin and Huang Lian suppressed it above, how can it endure Zhi Mu and Huang Bo attacking below? Calculating from spring to summer, continuous bitter-cold use enters the Heart first, transforming into fire. How dare one use Rou Gui to induce deficient Yang and release latent nature? To rectify the root, stick to Liu Wei Di Huang Wan combined with Sheng Mai San. Year-round use not only strengthens water to control Yang but achieves the subtle interaction of Metal generating Water. Why fear the residual toxicity of Gui Zhi and Fu Zi?