心阳曰。痘之发也。因天行时气。由父母胎毒。本乎五脏先天之症也。至于 子之发。亦因
天行时气。与伤寒相似。即所谓发斑伤寒也。自人受形而后。肥甘炙爆熏灼于胃腑。胃腑清
洁。其发也轻。胃腑垢腻。其发也重。此后天之症也。当发时。身热面赤。咳嗽。耳后筋红
若
青紫者重。眼睛水淋淋。总以表发升散为主。夫 本乎胃腑。传于肺家。与肝肾无涉。亦有
用黄连而得效者。诸火皆统于心故也。其起初发散之药。必用升麻。干葛。前胡。桔梗。薄
荷。防风。荆芥。蝉蜕。粘子。连翘。苏叶。亦可用。消食用谷芽。出不快。点子模糊。要
用麻黄。切不可用羌活。以其性燥。切不可用柴胡。以其为少阳胆经药。 子自肺胃两经
。与肝胆经无涉。若用柴胡。将胃火引入少阳。 后不无目疾。所谓引邪入门也。至山楂。
枳壳。麦芽三味。 中必用之药。然枳壳。山楂。治小儿乳疳。见点一二日。不骤用者。以
其味酸。酸则敛。 子以表发出透为主。若出到脚踝。则二味在所必用也。书云。寒凉过盛
未免有冰伏之患。故黄芩一味。不用于见点之初。而用于将剂之际。经云。胃火不清。不用
石膏之故。则发而为牙疳。口烂目痛。目赤。肺火不清。不用大黄之故。则热入大肠。流而
为泄泻下痢。此 后之症。皆由 前治不得法耳。
心阳子说：痘疹的发作，是因为感受了天行时气（流行性疫病之气），源于父母遗传的胎毒，这是基于五脏先天禀赋的病证。至于麻疹的发作，也是因为感受了天行时气，症状与伤寒相似，也就是所谓的“发斑伤寒”。自从人成形之后，如果饮食肥甘厚味、炙烤爆炒的食物熏灼胃腑，若胃腑保持清洁，则发病较轻；若胃腑积滞垢腻，则发病较重，这是后天因素导致的病证。在麻疹应当透发的时候，身体发热，面色发红，咳嗽，耳后筋脉发红，如果出现青紫色则病情较重，眼睛水汪汪流泪。治疗总以表散透发、升提发散为主。麻疹本源于胃腑，传变于肺脏，与肝、肾没有直接关系。也有使用黄连而取得疗效的，这是因为所有的火邪都统属于心的缘故。
起初用于发散的药物，必须使用升麻、干葛（葛根）、前胡、桔梗、薄荷、防风、荆芥、蝉蜕、粘子（牛蒡子）、连翘、苏叶等也可以使用。为了消食导滞，可以使用谷芽。如果疹点出不顺畅，点子模糊不清，就要用麻黄，切不可用羌活，因为羌活性味燥烈；切不可用柴胡，因为柴胡是少阳胆经的药引。麻疹主要涉及肺、胃两经，与肝胆经没有关联。如果使用柴胡，会将胃火引入少阳经，日后难免导致眼部疾病，这就是所谓的“引邪入门”（把病邪引入体内深处）。至于山楂、枳壳、麦芽这三味药，是治疗麻疹中必须使用的药物。然而，枳壳和山楂常用于治疗小儿乳疳（因乳食停滞引起的病症）。在疹点刚出现的一两天内，不急于大量使用这两味药，是因为它们味道酸涩，酸能收敛，而麻疹的治疗原则是以表发透达为主。如果疹点已经出到脚踝部位，那么这两味药就是必须使用的了。
医书说：寒凉药物使用过度，未免会有“冰伏”之患（指邪气被寒凉药物郁闭在内，不能透发），所以黄芩一味药，不在疹点初现时使用，而是在疹将透未透之际使用。经文说：如果胃火不清除，不使用石膏，就会引发牙疳、口烂、目痛、目赤等症状；如果肺火不清除，不使用大黄，热邪就会进入大肠，流注而导致泄泻、下痢。这些麻疹后期的病证，都是因为前期治疗不得法造成的。
Xinyang Zi stated: The eruption of smallpox is caused by the influence of epidemic qi (seasonal infectious pathogens), originating from fetal toxins inherited from parents, and is fundamentally a congenital condition rooted in the five zang organs. As for measles, its eruption is also due to the influence of epidemic qi, with symptoms similar to shaoyin cold damage (Shanghan), which is referred to as "macule-emitting cold damage." After human formation, if the stomach fu organ is scorched by rich, sweet, roasted, and fried foods, a clean stomach fu results in mild eruption, while a greasy and stagnant stomach fu results in severe eruption; this constitutes an acquired condition. During the eruptive phase, the body is hot, the face is red, there is coughing, and the tendons behind the ears are red; if they appear cyanotic or purplish, the condition is severe, and the eyes are watery. The treatment principle is primarily to release the exterior and promote dispersion. Measles originates in the stomach fu and transmits to the lung zang, having no direct involvement with the liver and kidney. There are cases where using Huanglian (Coptidis Rhizoma) yields effective results, because all fire pathogens are governed by the heart.
For initial dispersing formulas, Shengma (Cimicifugae Rhizoma), Gange (Puerariae Radix), Qianhu (Peucedani Radix), Jiegeng (Platycodonis Radix), Bohe (Menthae Haplocalycis Herba), Fangfeng (Saposhnikoviae Radix), Jingjie (Schizonepetae Spica), Chantui (Cicadae Periostracum), Nianzi (Arctii Fructus), Lianqiao (Forsythiae Fructus), and Zisu (Perillae Folium) should be used. Guoya (Oryzae Germ) can be used to resolve food stagnation. If the rash fails to emerge smoothly and appears blurred, Mahuang (Ephedrae Herba) must be used. Qianghuo (Notopterygii Rhizoma et Radix) must absolutely not be used due to its drying nature, and Chaihu (Bupleuri Radix) must absolutely not be used because it acts on the Shaoyang gallbladder meridian. Measles involves only the lung and stomach meridians and has no connection with the liver and gallbladder meridians. If Chaihu is used, stomach fire will be drawn into the Shaoyang meridian, inevitably leading to eye diseases later, which is termed "leading the pathogen into the house" (introducing evil into the interior).
Among ShanZha (Crataegi Fructus), Zhike (Aurantii Fructus Immaturus), and Maiya (Hordei Fructus Germinatus), these three herbs are essential in treating measles. However, Zhike and ShanZha are typically used to treat pediatric milk accumulation (Ru Gan). In the first one or two days after spots appear, they are not urgently employed because their sour taste causes astringency, whereas the main principle of measles treatment is exterior release and emergence. Once the rash reaches the ankles, these two herbs become indispensable.
Texts state that excessive use of cold-natured herbs may cause "ice-stagnation" (freezing of pathogens inside), so Huangqin (Scutellariae Radix) is not used at the initial appearance of spots but rather when the rash is about to fully emerge. Classics state: if stomach fire is not cleared and Shigao (Gypsum Fibrosum) is not used, conditions such as gangrenous gums, oral ulcers, eye pain, and redness of the eyes will develop. If lung fire is not cleared and Dahuang (Rhei Radix et Rhizoma) is not used, heat will enter the large intestine, flowing downward to cause diarrhea and dysentery. These post-eruption conditions of measles are all due to improper treatment during the pre-eruption stage.