痘谓之痘象形命名得其形为顺失其形为逆其色血而成圆者气为之形象乎天痘出而血从则
圆必周净附气而成晕者血为之影象乎地痘出而气从则晕必光明夫色之红者痘始出也白者毒未
解也黄者毒将解也干黄者毒尽解也灰白者血衰而气滞也黑者毒滞而血干也焦褐者气血枯也如
红变白白变黄者生红变紫紫变黑者死之兆也痘之稀者毒火不胜其气血自解间有气血弱而风寒
侵泄泻所陷
毒药所伤者亦难保痊稠如缀粟者气血不胜其毒火动生风表里不顺营卫不调七窍壅塞可易
疗乎间有气血胜者其形圆净不连其色红活不滞虽稠密可治
（疹即麻疹斑即斑毒疹小于痘而成片斑大于痘而红紫）
痘毒出于脏而深疹斑出于腑而浅疹痘受于运化之间是以经而易解有难解者为内实而外中
风寒也夫痘从外解疹从内解此不易常法若痘出之际毒趋百窍被风寒封固腠理兼气血壮盛湿蒸
火炽系动腑毒因而痘疹并出是皆不顺之候如痘出稀疏可以升麻汤解之疹散痘出其势自利若
痘太盛其疹虽解而气血已先受亏诚恐内虚不能收敛是尚难议有生其有夹斑者乃血太盛而卫气
疏缺不能密护脉络至太过之血夹痘上浮陈氏所谓三番痘疹是也如痘出起齐内必虚矣内虚则
斑从内解不解以升麻汤加归芍主之又有结痂后而发余毒者热盛煎熬内分其斑必烂此以解毒汤
加归芍防风甚则大连翘饮傅生肌散无不瘳矣若夹毒初出色赤如火乃毒滞不能宣发之故当服四
顺清凉饮利下一二次而退则血附气位急进四君子汤加黄 姜枣如泻不止加肉果药须预煎伺斑
退即服防其损陷期谓用药之机如用兵也
痘疹之所以称为“痘”，是因其形态而得名。得其形为顺证，失其形为逆证。痘疹由血构成而呈圆形，是因为有气的作用；其形象征着天。痘出而血随之，则痘体必然圆满洁净，依附于气而形成红晕，这是血的作用；其形象征着地。痘出而气随之，则红晕必然明亮。
至于颜色：红色表示痘刚发出；白色表示毒邪未解；黄色表示毒邪即将解除；干枯的黄色表示毒邪已完全解除；灰白色表示血虚而气滞；黑色表示毒邪停滞而血液枯竭；焦褐色表示气血枯败。如果颜色由红变白、由白变黄，是生机的征兆；如果由红变紫、由紫变黑，则是死亡的预兆。
痘疹稀疏的，说明毒火不能胜过气血，气血自然能化解毒邪；间或有因气血虚弱，被风寒侵袭，或因泻下导致毒邪内陷，或被毒药所伤的情况，也难以保全痊愈。痘疹稠密如连缀的粟米，说明气血不能胜任毒火，导致动风，表里不和，营卫不调，七窍壅塞，这样还能轻易治疗吗？间或有气血旺盛者，其痘形圆净不相连，色泽红润鲜活不晦暗，虽然稠密也可以治愈。
痘毒出于脏而位置深，疹和斑出于腑而位置浅。疹和痘受病于运化之间，所以容易通过经络化解。有难化解的，是因为内部实热而外部感受了风寒。痘从体表解除，疹从体内解除，这是不变常法。如果在痘发出的时候，毒邪趋向百窍，被风寒封闭腠理，兼之气血壮盛，湿蒸火炽，牵动腑毒，因而痘疹并出，这都是不顺的证候。
如果痘出稀疏，可以用升麻汤来解除；疹散后痘出，其势自然顺利。如果痘太盛，虽然疹解，但气血已经先受亏损，诚恐内部虚弱不能收敛，这尚难议论是否有生机。如果有夹带斑毒的，乃是血太盛而卫气疏缺，不能严密保护脉络，导致过盛的血液夹带痘毒上浮，这就是陈氏所说的“三番痘疹”。如果痘发出后起齐，内部必然虚弱；内部虚弱则斑从内部解除，若不解，用升麻汤加当归、芍药为主方。又有结痂后而发余毒的，热盛煎熬，内部分化出斑，必然溃烂，此用解毒汤加当归、芍药、防风，严重的用大连翘饮，外傅生肌散，没有不痊愈的。如果夹毒初发，颜色赤如火，乃毒邪停滞不能宣发的缘故，应当服用四顺清凉饮，利下一两次而退，则血附气位，急进四君子汤加黄芪、生姜、大枣。如果泻不止，加肉豆蔻。药物须预先煎好，等待斑退即服，以防其损伤陷下。所谓用药的时机，就像用兵一样。
The term "dou" (smallpox/variolous rash) is named based on its morphology. Obtaining the correct form indicates a favorable prognosis (Shun), while losing it indicates an unfavorable prognosis (Ni). The dou is formed by blood into a round shape due to the influence of Qi; this image corresponds to Heaven. When the dou erupts and blood follows, the dou must be complete and clean, attaching to Qi to form a halo; this represents the function of Blood; this image corresponds to Earth. When the dou erupts and Qi follows, the halo must be bright.
Regarding color: Red indicates the initial eruption of the dou; White indicates that the pathogenic toxin has not yet resolved; Yellow indicates that the toxin is about to resolve; Dry yellow indicates that the toxin has completely resolved; Grayish-white indicates blood deficiency with Qi stagnation; Black indicates toxin stagnation with dried blood; Scorched brown indicates exhaustion of Qi and Blood. If the color changes from red to white, or from white to yellow, it is a sign of life; if it changes from red to purple, or from purple to black, it is an omen of death.
When the dou are sparse, the pathogenic fire cannot overcome the Qi and Blood, allowing the Qi and Blood to naturally resolve the toxin. Occasionally, due to weak Qi and Blood invaded by Wind-Cold, or toxin sinking inward due to diarrhea, or injury by toxic drugs, recovery may be difficult to ensure. When the dou are dense, resembling connected millet grains, it indicates that Qi and Blood cannot withstand the pathogenic fire, leading to internal wind stirring, disharmony between the interior and exterior, imbalance of Ying and Wei, and blockage of the seven orifices; can such a condition be easily treated? Occasionally, those with strong Qi and Blood have dou that are round, clean, and non-confluent, with ruddy and vibrant color without stagnation; even if dense, they are treatable.
(Zhen refers to measles, Ban refers to macular rash/toxin. Zhen is smaller than dou and appears in patches; Ban is larger than dou and is red-purple.)
Dou toxin originates from the Zang organs and is deep; Zhen and Ban originate from the Fu organs and are superficial. Zhen and Dou are affected during the process of transformation and transportation, thus they are easy to resolve via the meridians. Cases that are difficult to resolve occur when there is internal excess combined with external invasion of Wind-Cold. Dou resolves from the exterior, while Zhen resolves from the interior; this is the unchanging standard method. However, at the time of dou eruption, if the toxin tends toward the hundred orifices,被封固 (sealed) by Wind-Cold closing the Couli (pores), coupled with robust Qi and Blood, steaming dampness, and blazing fire, which stirs up Fu organ toxin, resulting in simultaneous eruption of dou and zhen, these are all unfavorable signs.
If the dou are sparse, Shengma Tang (Cimicifugae Decoction) can be used to resolve them; after the zhen disperses and the dou erupts, the progression will naturally be smooth. If the dou are too excessive, although the zhen resolves, the Qi and Blood have already been depleted; one must fear that internal deficiency prevents convergence, making it difficult to predict survival. In cases with concurrent Ban (macular rash), it is due to excessive Blood and deficient Wei Qi (Defensive Qi), which fails to tightly protect the collaterals, causing excessive Blood to carry Dou toxin upward floating. This is what Chen referred to as "Sanfan Douzhen" (Three-turn Dou-Zhen). Once the dou erupts and reaches full development, the interior must be deficient; if the interior is deficient, the Ban resolves from within. If it does not resolve, use Shengma Tang modified with Dang Gui (Angelicae Sinensis Radix) and Bai Shao (Paeoniae Radix Alba) as the main prescription. There are also cases where residual toxin erupts after scabbing forms; intense heat causes internal differentiation of Ban, leading to ulceration. Treat with Jiedu Tang (Detoxification Decoction) added with Dang Gui, Bai Shao, and Fang Feng (Saposhnikoviae Radix); for severe cases, use Da Lianqiao Yin (Large Forsythia Drink) externally applied with Shengji San (Flesh-Regenerating Powder); there will be no failure to heal. If concurrent toxin erupts initially with color red like fire, it is due to toxin stagnation preventing dissemination. One should administer Sishun Qingliang Yin (Four-Obedience Cooling Clearing Drink), inducing defecation once or twice to reduce symptoms, then the Blood adheres to Qi position; urgently advance Sijunzi Tang (Four Gentlemen Decoction) added with Huang Qi (Astragali Radix), Sheng Jiang (Zingiberis Rhizoma Recens), and Da Zao (Jujubae Fructus). If diarrhea persists, add Rou Dou Kou (Myristicae Semen). Medications must be pre-decocted and administered immediately after the Ban recedes to prevent damage and sinking. The timing of medication is likened to military strategy.