麻症腹痛，由于食滞凝结，热毒不能宣发于外，故有时曲腰啼叫，两眉频蹙，须用
加味平胃散治之。若不因食积，全是热毒内结，治宜疏托，使疹子尽出，痛自止矣。没
后见此，又宜清凉解毒，使毒内消，痛亦随减。
麻本火候，大便溏泻，黄褐色为正。初热正出时，下利数次，毒瓦斯得泄，但不宜多，
久久则脾气下陷。毒难发越，后恐变痢，初起作泻者，以升麻葛根汤，加赤苓、猪苓、泽
泻主之。已出作泻者，以黄连解毒汤主之。若水泻黄色有沫，小便赤，唇燥口干，乃毒热
移入肠胃，传化失常，亦宜清凉利水，俱不可用温热之剂。如自利不止，水泻频数，最
为恶候。若疹子稠密，或紫红色，则又无妨。盖以毒在大肠，非泻不解，宜平胃散加黄连、
葛根、连翘以解之。疹子发透，自然泻止。有没后仍不止者，此未出尽，再用前药，倍连
翘、黄连，加木通，泽泻、牛蒡子分利之，切勿治以固涩，致腹胀痞满，喘急不治。景岳
以为泻利一症，果由疹毒，固不可以温补，若其人脾气本弱，或过用寒凉之药，或误食生
冷，致伤脾胃，而为泄泻者，虽曰由疹而发，而实非疹毒之病矣。但察其无热症热脉，而
兼色白气馁者，便宜温胃饮、五君子煎、胃关煎之类主之。若执谓疹毒不可温，则无不
危矣。
麻疹引起的腹痛，是由于食物停滞凝结，热毒不能向外宣发所致，因此有时会出现弯腰啼哭、双眉紧皱的症状，需要用加味平胃散来治疗。如果不是因为食积，而是完全由热毒内结引起，治疗应当采用疏解透托的方法，使疹子全部发出，疼痛自然停止。在疹子消退后如果出现这种情况，又适宜用清凉解毒的方法，使体内毒邪消散，疼痛也随之减轻。
麻疹本属火性之病，大便溏泻且呈黄褐色为正常现象。在初热期疹子刚开始发出时，腹泻数次，有助于毒气宣泄，但不宜过多，如果时间长久则会导致脾气下陷，毒邪难以发散透越，后期恐怕会转变为痢疾。初期出现泄泻的，以升麻葛根汤为主方，加入赤茯苓、猪苓、泽泻主治；疹子已经发出后出现泄泻的，以黄连解毒汤主治。如果是水样黄色便且有泡沫，小便颜色深红，嘴唇干燥口干，这是毒热移入肠胃，导致传化功能失常，也适宜用清凉利水的方法治疗，都不可使用温热性质的药剂。如果是自发性腹泻不止，水泻频繁，这属于非常危险的征候。但如果疹子稠密，或者呈现紫红色，那么则无妨。这是因为毒邪在大肠，不通过腹泻无法解除，适宜用平胃散加入黄连、葛根、连翘来解之。疹子发透之后，腹泻自然会停止。如果在疹子消退后仍然不止泻，这是因为疹毒未出尽，再用前面的药物，加倍使用连翘、黄连，加入木通、泽泻、牛蒡子进行分利疏导，千万不要用固涩止泻的方法，以免导致腹胀痞满、气喘急促等无法救治的后果。张景岳认为，泄泻这一症状，如果确实是由疹毒引起，固然不可以用温补法；但如果患者本身脾气虚弱，或者过度使用寒凉药物，或者误食生冷食物，导致损伤脾胃而引发的泄泻，虽然说是由麻疹引发，但实际上并非疹毒本身的疾病了。只要观察其没有热症和热脉，并且兼有面色苍白、气息微弱的表现，就适宜用温胃饮、五君子煎、胃关煎之类的方剂主治。如果固执地认为疹毒不可用温补法，那么就没有不陷入危境的。
Abdominal pain caused by measles is due to food stagnation and concretion, where the heat-toxin cannot be vented outward. Consequently, patients may sometimes curl their waists and cry out, with frequent frowning of the eyebrows. It should be treated with Jiawei Pingwei San (Modified Pingwei Powder). If it is not due to food accumulation but entirely caused by internal binding of heat-toxin, the treatment should focus on dispersing and supporting eruption, allowing the rash to fully emerge, after which the pain will cease naturally. If this occurs after the rash has subsided, it is appropriate to use cooling and detoxifying methods to dissipate the internal toxin, thereby reducing the pain.
Measles is inherently a fire-heat condition; loose stools that are yellowish-brown are considered normal. During the initial fever stage when the rash is just beginning to erupt, defecating several times helps to vent the toxic qi, but it should not be excessive. Prolonged diarrhea can lead to sinking of Spleen Qi, making it difficult for the toxin to disperse and erupt, potentially transforming into dysentery later. For diarrhea occurring at the onset, Shengma Gegen Tang (Cimicifugae et Puerariae Decoction) combined with Chi Ling (Polyporus umbellatus), Zhu Ling (Polyporus cocos), and Ze Xie (Alisma Orientale) is indicated. For diarrhea occurring after the rash has erupted, Huanglian Jiedu Tang (Coptis Decoction for Detoxification) is indicated. If there is watery yellow stool with foam, dark urine, dry lips, and a dry mouth, this indicates that heat-toxin has shifted into the intestines and stomach, disrupting transformation and transportation. Cooling and diuretic methods are appropriate here; warm-natured agents must not be used. If spontaneous diarrhea persists with frequent watery stools, this is a ominous sign. However, if the rash is dense or purple-red, there is no cause for concern. This is because the toxin resides in the large intestine and cannot be resolved without diarrhea. Pingwei San added with Huanglian (Coptidis Rhizoma), Gegen (Puerariae Lobatae Radix), and Lianqiao (Forsythiae Fructus) should be used to resolve it. Once the rash is fully expressed, the diarrhea will stop naturally. If diarrhea continues after the rash has subsided, it indicates that the toxin has not been fully expelled. The previous prescription should be used again, with doubled amounts of Lianqiao and Huanglian, plus Mu Tong (Akebiae Caulis), Ze Xie, and Niu Bang Zi (Arctii Fructus) to promote differentiation and drainage. Do not use astringent treatments to stop diarrhea, as this may lead to abdominal distension, fullness, panting, and untreatable conditions. Zhang Jingyue stated that regarding diarrhea, if it is indeed caused by measles toxin, warming tonification is certainly contraindicated. However, if the patient has inherent weak Spleen Qi, or has overused cold-cooling medicines, or mistakenly consumed raw/cold foods, damaging the Spleen and Stomach and causing diarrhea, although triggered by measles, it is essentially not a disease of measles toxin. As long as one observes the absence of heat symptoms and heat pulse, accompanied by pale complexion and faint qi, formulas such as Wenwei Yin (Warming Stomach Drink), Wu Junzi Jian (Five Gentlemen Decoction), or Weiguan Jian (Stomach Gate Decoction) are appropriate. If one rigidly adheres to the view that measles toxin cannot be treated with warming methods, danger is inevitable.