火壅血燥津液竭。大便因之而秘涩。无分先后急通润。稽延日久变紫黑。
大便秘结者。乃火壅血燥而耗精液故也。麻之为候。大便宜滑。如黄褐色。乃为正候。若大便
秘而不通。大非所宜。无论先后日期。但大便秘者。急当用通润清凉之剂。初时大便难通而坚结
难出者。宜微润之。不可过利。以通幽汤。去升麻、甘草、熟地黄。加火麻仁、枳实、黄连治之。如
麻未出之初。有面色或青或红、或唇紫、或烦闷、而大便秘而不通者。宜以大承气汤。去浓朴。加
连翘、牛蒡子、防风、葛根、荆芥穗下之。使毒从大肠经而出。然后再用毒发表汤。（见第五条）
去升麻、桔梗、甘草。以发出麻疹。其症自痊。若正收及收后。大便不通者。则宜用大通润之剂。
以四顺清凉饮治之。甚则用河间凉膈散（见二十六条）以通利之。若大便秘结。发热身痛者。以
大柴胡汤主之。腹痛气喘者。以前胡枳壳汤（见五十一条）去炙甘草。加姜汁炒芥子治之。凡麻见
便秘之症。急宜早治。慎勿迟延日久。则麻变焦紫枯黑而难救矣。
通幽汤 升清阳。降浊阴。治噎塞、便秘。
油当归（二钱五分） 升麻（醋浸三分） 桃仁（研如泥一钱） 红花 生甘草 炙甘草（各五
分） 熟地黄 生地黄（各一钱五分） 水煎。以药汁磨槟榔五分。对药稍热服。（加火麻仁、大黄
名当归润肠汤）
大承气汤
大黄（酒洗四钱） 芒硝（三钱） 浓朴 枳实（各七分） 水煎服。
四顺清凉饮（一名四顺饮）
当归 赤芍 大黄（酒蒸） 甘草（各等分） 水煎。入生白蜜一二匙。对药热服。
大柴胡汤 治表症未除。里症又急。汗下兼行用之。
柴胡（一钱） 黄芩 芍药（各三分） 枳实（三分） 半夏（五分） 大黄（二分） 姜、枣引。
Fire pathogen stagnates, blood becomes dry, and body fluids are exhausted. Consequently, the stool becomes constipated and difficult to pass. Regardless of whether it occurs early or late in the disease course, urgent treatment with purgative and moistening methods is required. If delayed for a long time, the rash may turn purple-black due to toxin retention.
Constipation is caused by fire pathogen stagnation and blood dryness consuming essence and fluids. In normal measles cases, the stool should be smooth and yellowish-brown; this is the normal manifestation. If the stool is constipated and obstructed, it is highly inappropriate (referring to standard measles care). Regardless of the number of days since onset, if constipation occurs, urgent administration of agents that purge, moisten, and clear heat is necessary. In the initial stage, when stool is hard and difficult to pass, mild moistening purgation should be used rather than excessive purging. Tongyou Decoction can be modified by removing Shengma (Rhizoma Cimicifugae), Gancao (Radix Glycyrrhizae), and Shudihuang (Radix Rehmanniae Preparata), and adding Huomaren (Semen Cannabis), Zhishi (Fructus Aurantii Immaturus), and Huanglian (Rhizoma Coptidis) for treatment. In the early stage before measles eruption, if the patient presents with bluish or reddish complexion, purple lips, irritability, and chest oppression, accompanied by constipation, Dachengqi Decoction should be used. Remove Nongpo (Cortex Magnoliae Officinalis), and add Lianqiao (Fructus Forsythiae), Niubangzi (Fructus Arctii), Fangfeng (Radix Saposhnikoviae), Gegen (Radix Puerariae), and Jingjiesui (Flos Schizonepetae) to purge the toxins via the Large Intestine meridian. Subsequently, use Fabiao Tang (see Article 5) to release the measles, removing Shengma (Rhizoma Cimicifugae), Jiegeng (Radix Platycodonis), and Gancao (Radix Glycyrrhizae), so that symptoms will naturally resolve. If constipation occurs during the resolution phase or after the resolution of measles, strong purgative and moistening agents should be used, such as Sishun Qingliang Yin. For severe cases, Hejian Liangge San (see Article 26) can be used to promote bowel movement. If constipation is accompanied by fever and body pain, Da Chaihu Decoction is the primary formula. If abdominal pain and wheezing occur, Qianhu Zhike Tang (see Article 51) should be used, removing Zhi Gancao (Radix Glycyrrhizae Preparata) and adding Mustard Seed stir-fried with ginger juice. Any case of measles presenting with constipation requires early treatment; do not delay, lest the rash become scorched, purple, black, and incurable.
Tongyou Decoction: Raises clear yang, descends turbid yin, treats dysphagia and constipation.
You Danggui (Radix Angelicae Sinensis Oiled, 2.5 qian) Shengma (Rhizoma Cimicifugae, soaked in vinegar, 3 fen) Taoren (Semen Persicae, ground into paste, 1 qian) Honghua (Flos Carthami) Sheng Gancao (Radix Glycyrrhizae Raw) Zhi Gancao (Radix Glycyrrhizae Prepared) Shudihuang (Radix Rehmanniae Preparata) Sheng Dihuang (Radix Rehmanniae Raw) (each 1.5 qian). Decoct in water. Grind Binglang (Areca Seed, 5 fen) with the decoction liquid, and take warm. (Adding Huomaren (Semen Cannabis) and Dahuang (Radix et Rhizoma Rhei) creates Danggui Runchang Tang).
Dachengqi Decoction
Dahuang (Radix et Rhizoma Rhei, washed with wine, 4 qian) Mangxiao (Natrii Sulfas, 3 qian) Nongpo (Cortex Magnoliae Officinalis) Zhishi (Fructus Aurantii Immaturus) (each 7 fen). Decoct in water and take.
Sishun Qingliang Yin (also known as Sishun Yin)
Danggui (Radix Angelicae Sinensis) Chishao (Radix Paeoniae Rubra) Dahuang (Radix et Rhizoma Rhei, steamed with wine) Gancao (Radix Glycyrrhizae) (equal parts). Decoct in water. Add 1-2 spoons of raw white honey, and take warm with the decoction.
Da Chaihu Decoction: Treats cases where exterior syndrome persists while interior syndrome is urgent, requiring simultaneous sweating and purging.
Chaihu (Radix Bupleuri, 1 qian) Huangqin (Radix Scutellariae) Shaoyao (Radix Paeoniae Alba/Lactiflora) (each 3 fen) Zhishi (Fructus Aurantii Immaturus, 3 fen) Banxia (Rhizoma Pinelliae, 5 fen) Dahuang (Radix et Rhizoma Rhei, 2 fen). Use Shengjiang (Rhizoma Zingiberis Recens) and Zao (Fructus Jujubae) as guides.