时疫夹脾虚者，为难治矣，夹肾虚者更难。时疫属热证，肾气虚则手足冷；时疫属实邪，肾气虚则眩晕惊悸，
腰膝萎软。肾虚之中，又有阴虚、阳虚之分。时疫必待汗、下、清而后解。阳虚者，一经汗、下、清则脱绝之证
随见；阴虚者，一经汗、下则枯竭之证随见，必须时时谛察。
凡在表时，见腰痛异常，小便频数，膝胫冷软，其人平日非有淋浊、阳萎，即系遗泄、好内，须询明。于通表
药中加人参、白芍，阳虚兼杜仲，阴虚兼知母，以照顾肾气，免后来意外之变。若入里当下，必以陶氏黄龙汤为
主；当清，必以人参白虎汤为主。或屡清、屡下而热更甚，舌上燥而无苔；或有黑苔，愈清而愈长；或有燥苔，
愈下而愈燥，此皆肾虚之证。察其阳明，无实邪可据，当从肾虚治，以六味地黄汤易生地，加知柏。王太仆所谓∶
寒之不寒，责以无水，壮水之主，以制阳光者，此也。或
仍不应，则合生脉散以滋水之上源；或用四物汤流通经络。似此热势燎原，非杯水所能救，必大作汤液，药味必
以两计，汤液必以斗计，乃有济耳。见几若早，十救二、三；涸竭已见，十难救一；或更兼脾胃败证，
如呕、呃、哕、利之类，汤药不下，百难救一矣。
疫证亡血有三。
其一，未病之先，素亡血而阴虚，一受疫则邪热乘虚煎熬，亡阴最易。解表清里，用药必步步照顾荣血，如九
味羌活汤之用生地，人参败毒散之用人参是也。
其二，当受病之时，忽然吐衄，女子崩漏，甚至血晕昏厥，势甚危急，亦疫证常有也。病家但知血之可骇，往
往不知受疫；医家亦忽其客邪，惟汲汲于止血、清凉、滋补，多至危殆。不知血由疫逼，惟当治疫，疫邪解而血自
止。此证不遽见于疫在表时，而见于发热数日之后，人犹易知，惟疫郁于阴经而暴见此证者难识，以其证外无头
痛、发热之可据耳。但见微恶寒而大作呕，急当视其气、色、神、脉、舌苔，若舌有白苔，气色有一、二疫象，即
是疫毒无疑。以达原饮为主，呕加藿香，胀加青皮，但治疫毒，血证自已。若脱血太甚而气欲绝者，加人参以固中
气，俟疫证传变归经，然后按经治之，此疫证兼血之最危者。
其三，疫邪大张之后，烦热、燥渴之余，而见亡血证，则又瘟疫常态，详后血证各条。
时疫夹杂脾虚的，已经属于难治之症，而夹杂肾虚的更加难以治疗。时疫属于热证，若肾气虚弱，则会出现手足发冷；时疫属于实邪致病，若肾气虚弱，则会出现眩晕、惊悸、腰膝萎软无力等症状。在肾虚之中，又分为阴虚和阳虚两种情况。时疫病必须通过发汗、攻下、清热等方法才能解除。若是阳虚患者，一经使用发汗、攻下、清热法，就会随即出现阳气脱绝的危重证候；若是阴虚患者，一经使用发汗、攻下法，就会随即出现阴液枯竭的危重证候，因此必须时刻仔细诊察。
凡是在病邪在表阶段，如果见到腰痛异常剧烈、小便频数、膝盖和小腿寒冷软弱，询问其平日是否有淋浊（排尿涩痛或尿出白浊）、阳痿，或者是遗精滑泄、喜好房事等情况，必须详细查明。在治疗表证的药物中加入人参、白芍；若是阳虚兼见者，加入杜仲；若是阴虚兼见者，加入知母，以此来顾护肾气，避免日后发生意外的变故。如果病邪入里需要攻下，必须以陶华氏的黄龙汤为主方；如果需要清热，必须以人参白虎汤为主方。或者经过多次清热、攻下后，热势反而更盛，舌面干燥且无苔；或者有黑苔，越是清热黑苔越长；或者有燥苔，越是攻下舌苔越燥，这些都是肾虚的表现。诊察阳明经，没有实邪可依据，就应当从肾虚论治，用六味地黄汤去掉生地黄，加入知母和黄柏。正如王冰（王太仆）所说：“寒之不寒，责以无水”，即壮水之主（滋补肾阴），以制约阳光（亢盛的阳热），说的就是这种情况。如果仍然无效，则合用生脉散来滋补水之上源（肺阴）；或者使用四物汤来流通经络。像这样热势如燎原大火，不是杯水车薪所能挽救的，必须大量煎煮汤药，药味剂量必须以“两”计算，汤药总量必须以“斗”计算，这样才能起到救治作用。如果能及早发现征兆，十个人可以救活二三个；如果阴液枯竭的症状已经显现，十个人很难救活一个；如果再兼有脾胃败坏的证候，如呕吐、呃逆、干哕、腹泻等，导致汤药无法服下，那么一百个人中很难救活一个了。
瘟疫病症中涉及亡血（失血）的情况有三种。
第一种，在发病之前，素来就有失血病史且阴虚的人，一旦感染疫邪，邪热就会乘虚煎熬阴液，最容易导致亡阴。在解表和清里的用药过程中，必须步步照顾营血，比如九味羌活汤中使用生地黄，人参败毒散中使用人参，就是这个道理。
第二种，在患病当时，突然发生吐血、鼻衄，女子崩漏（非经期大量出血或淋漓不断），甚至出现血晕昏厥，形势非常危急，这也是疫证中常有的情况。病人家属只知道失血令人惊恐，往往不知道是感染了疫邪；医生也忽略了外来的疫邪，只急切地致力于止血、清凉、滋补，这往往会导致病情危殆。不知道血液妄行是由疫邪逼迫所致，只应当治疗疫邪，疫邪解除后出血自然停止。这种证候不急于在疫邪在表时出现，而是在发热数日之后才出现，人们还容易知晓；唯独疫邪郁闭在阴经而突然爆发此证的，难以识别，因为其外在没有头痛、发热等可依据的症状。但只要见到轻微恶寒并伴有剧烈呕吐，就应紧急观察其气色、神态、脉象、舌苔，如果舌上有白苔，气色中有一两个疫病的征象，就可以确定是疫毒无疑。以达原饮为主方，呕吐加藿香，腹胀加青皮，只要治疗疫毒，血证自然停止。如果失血过多导致气欲绝，加入人参以固护中气，等到疫证传变归经后，然后再按照经络辨证治疗，这是疫证兼夹失血中最危重的情况。
When a plague disease (Shi Yi) is complicated by Spleen Qi deficiency, it is difficult to treat; when complicated by Kidney Qi deficiency, it is even more difficult. Plague diseases belong to heat syndromes; if Kidney Qi is deficient, the hands and feet become cold. Plague diseases involve excess pathogens; if Kidney Qi is deficient, symptoms such as vertigo, palpitations, and flaccidity/weakness of the lower back and knees occur. Within Kidney deficiency, there are further distinctions between Yin deficiency and Yang deficiency. Plague diseases must be resolved through sweating (Han), purging (Xia), and clearing heat (Qing). If the patient has Yang deficiency, the application of sweating, purging, or clearing methods will immediately lead to signs of Yang collapse (Tuo Jue); if the patient has Yin deficiency, the application of sweating or purging methods will immediately lead to signs of Yin exhaustion. Therefore, careful observation is required at all times.
During the stage where the pathogen is in the exterior, if severe lower back pain, frequent urination, and coldness with weakness in the knees and shins are observed, one must inquire whether the patient historically suffered from strangury (Lin Zhuo) or impotence (Yang Wei), or had a history of seminal emission/nocturnal pollution (Yi Xie) and excessive sexual activity. This must be clarified clearly. In formulas for releasing the exterior, add Ren Shen (Ginseng Root) and Bai Shao (White Peony Root). For those with Yang deficiency, also add Du Zhong (Eucommia Bark); for those with Yin deficiency, also add Zhi Mu (Anemarrhena Rhizome), to protect Kidney Qi and prevent unexpected complications later. If the pathogen enters the interior requiring purging, Tao Shi's Huang Long Tang (Yellow Dragon Decoction) should be the primary formula; if clearing heat is required, Ren Shen Bai Hu Tang (Ginseng White Tiger Decoction) should be the primary formula. Or, if repeated clearing and purging result in intensified heat, a dry tongue without coating, black coating that grows longer despite clearing, or dry coating that becomes drier despite purging, these are all signs of Kidney deficiency. Upon examining the Yangming channel and finding no evidence of excess pathogens, treatment should proceed based on Kidney deficiency, using Liu Wei Di Huang Tang (Six-Ingredient Rehmannia Pill) with Sheng Di Huang (Rehmannia Root) replaced, and adding Zhi Mu and Huang Bo (Phellodendron Bark). As Wang Tai Pu (Wang Bing) stated: "If cooling does not cool, blame the lack of water"; this refers to strengthening the master of water (nourishing Kidney Yin) to control the solar flare (hyperactive Yang). If there is still no response, combine with Sheng Mai San (Generate the Pulse Powder) to nourish the upper source of water (Lung Yin); or use Si Wu Tang (Four Substance Decoction) to unblock the meridians. When heat spreads like a prairie fire, a cup of water cannot save the situation. One must prepare large quantities of decoctions, measuring herbs in *liang* (taels) and total liquid volume in *dou* (pecks), to have any chance of success. If recognized early, two or three out of ten may be saved; if exhaustion is already evident, it is hard to save one out of ten; if accompanied by signs of Spleen and Stomach failure, such as vomiting, hiccuping, dry heaving, or diarrhea, preventing oral intake of medicine, it is hard to save one out of a hundred.
There are three types of blood loss (Wang Xue) associated with plague syndromes.
First, prior to illness, if the patient has a history of chronic blood loss and Yin deficiency, once infected by the plague, the pathogenic heat will torment the deficiency, making Yin exhaustion most likely. In both exterior-releasing and interior-clearing treatments, care must be taken at every step to protect Ying Blood (Nutritive Blood). Examples include the use of Sheng Di Huang in Jiu Wei Qiang Huo Tang (Nine-Ingredient Notopterygium Decoction) and Ren Shen in Ren Shen Bai Du San (Ginseng Detoxification Powder).
Second, upon contracting the disease, sudden epistaxis (bi ni) or hematemesis (tu xue), uterine bleeding (beng lou) in women, or even syncope due to blood loss (xue yun) can occur, presenting a critical emergency. This is common in plague syndromes. Families often only fear the blood loss and fail to recognize the plague infection; physicians often overlook the external pathogen and focus urgently on stopping bleeding, cooling, and tonifying, which often leads to critical danger. They do not realize that the bleeding is forced by the plague pathogen; one should treat the plague, and once the pathogen is resolved, the bleeding will stop spontaneously. This syndrome does not typically appear when the plague is in the exterior, but rather after several days of fever, which is easier to recognize. However, when plague pathogens stagnate in the Yin channels and suddenly manifest this syndrome, it is difficult to identify because there are no external signs like headache or fever to rely on. But if slight aversion to cold is seen accompanied by severe vomiting, urgently observe the Qi, complexion, spirit, pulse, and tongue coating. If there is a white tongue coating and the complexion shows one or two signs of plague, it is undoubtedly plague toxin. Use Da Yuan Yin (Reach the Original Drink) as the main formula; add Huo Xiang (Patchouli) for vomiting, and Qing Pi (Citrus Peel) for distension. By treating only the plague toxin, the blood syndrome will resolve itself. If blood loss is too severe and Qi is about to collapse, add Ren Shen to consolidate Middle Qi. Wait until the plague syndrome transmits and settles into its respective channel, then treat according to the channel. This is the most critical case of plague complicated by blood loss.
Third, after the plague pathogen has surged vigorously, following periods of irritability, heat, dryness, and thirst, the appearance of blood loss syndromes is a normal pattern of plague, detailed in subsequent sections on blood syndromes.