【歌】肠风脏毒从何别？肠胃停寒与蓄热。血浊色黯脏毒因，蕴毒于中几 荚。肠风血色清且鲜，外邪随
感而随泄。
【论】人之肠胃不虚，则邪气无由而入。或坐卧风湿，醉饱房劳，生冷停寒，酒面积热，以致荣血失道，
渗入于大肠之经，此肠风、脏毒之所由作也。故挟热下血暴发者，则血色清鲜，腹中有痛；若挟寒而下血兼积
久者，则血色凝浊而色黯，腹内微痛。故暴病则为肠风，盖肠风者，邪从外入，随感而随见是也；积久始发，
浊者为脏毒，盖脏毒者，久积其毒而始发是也。有先血后便者，其血来也近；先便后血者，其血来也远。俗谓
粪前、粪后，非也。若脏毒证积热日久，
忽郁于寒，实非寒也，不可以标寒而用热剂也。
肠风
丹溪云∶肠风独在胃、大肠出。若兼风者，苍术、秦艽、香附之类。便血久远伤血致虚，并麻风、癣疮见
于面者，椿皮丸。又方肠风下血，香附一两、枳壳七钱、芎、归各五钱、槐角、甘草各二钱，姜、枣煎服。
椿皮丸
治肠风致虚。
龟板（二两，酥炙） 升麻（五钱） 香附（五钱） 白芍药（两半） 侧柏叶（一两） 椿根白皮（七钱半）
末之，粥丸桐子大，每服六十丸，以四物汤加白术、黄连、甘草、陈皮作末调汤送下。
脏毒
寒食积毒于肠，日久始发，曰脏毒。积热者，三黄丸。协湿，地榆丸。协寒，败毒散。次以芎归汤随其寒
热而调之。热加茯苓、槐花；寒加木香、茯苓。（方见头痛。）收功，四物汤加参、 、槐角。
三黄丸
治积热便血。
苍术（一两半） 陈皮（一两半） 黄连（七钱半） 连翘（半两）
末之，生地捣烂糊丸，桐子大，白汤下。
地榆丸
治脏毒挟湿者。
白术（半两） 黄柏（炒，二钱） 生地黄（二钱） 白芍药（二钱） 地榆（二钱） 黄芩（炒，二钱）
香附（二钱）
共末，蒸饼为丸。
败毒散
治协寒便血。
羌活（一钱，去芦） 独活（一钱，去芦） 柴胡（一钱，去毛） 前胡（一钱，去芦） 枳壳（炒，八
分） 茯苓（八分，去皮） 川芎（七分） 甘草（五分，炙） 桔梗（八分，去芦）
姜三片，水二钟，煎一钟服。
【歌诀】如何辨别肠风与脏毒？关键在于肠胃中是停留寒邪还是蓄积热邪。血色浑浊、颜色暗紫的是脏毒，这是因为毒素蕴结在体内所致；而肠风的血色清澈且鲜艳，是因为外感邪气随感受随即排出。
【论述】人的肠胃如果不虚弱，邪气就没有途径侵入。或者因坐卧于风湿之中，或因醉酒饱食、房劳过度，导致生冷之物停滞产生寒邪，酒食积聚产生热邪，致使营血运行失常，渗入大肠经脉，这就是肠风和脏毒产生的原因。所以，夹带热邪而下血且发病急骤的，血色清澈鲜红，腹部有疼痛感；若是夹带寒邪而下血且病程长久的，血色凝滞浑浊且颜色暗紫，腹部轻微疼痛。因此，突发疾病称为肠风，所谓肠风，是指邪气从外部侵入，随感受随即显现；病程长久才发作，血色浑浊的是脏毒，所谓脏毒，是指毒素久积之后才发作。有先出血后排便的，说明出血部位离肛门近；先排便后出血的，说明出血部位离肛门远。世俗所说的粪前、粪后出血是不准确的。如果脏毒证候积热日久，忽然郁结于寒象之中，其实并非真正的寒证，不能因为表面的寒象而使用热性药物。
肠风
朱丹溪说：肠风独发于胃和大肠。如果兼夹风邪，可用苍术、秦艽、香附之类的药物。便血日久损伤血液导致虚证，以及麻风病、癣疮出现在面部的情况，用椿皮丸。另一个方子治疗肠风下血，用香附一两、枳壳七钱、川芎和当归各五钱、槐角和甘草各二钱，加生姜、大枣煎服。
椿皮丸
治疗肠风导致的虚证。
龟板（二两，用酥油炙烤）、升麻（五钱）、香附（五钱）、白芍药（一两半）、侧柏叶（一两）、椿根白皮（七钱半）。研成细末，用米粥调和制成如梧桐子大小的丸剂，每次服用六十丸，用四物汤加入白术、黄连、甘草、陈皮研成的粉末调汤送服。
脏毒
寒湿食物积毒于肠道，日久才发作，称为脏毒。如果是积热引起的，用三黄丸。如果兼夹湿气，用地榆丸。如果兼夹寒邪，用败毒散。随后用芎归汤根据其寒热属性进行调理。热证加茯苓、槐花；寒证加木香、茯苓。（方剂见头痛章节）收功阶段，用四物汤加入人参、黄芪、槐角。
三黄丸
治疗积热导致的便血。
苍术（一两半）、陈皮（一两半）、黄连（七钱半）、连翘（半两）。研成细末，用生地黄捣烂取汁糊制丸剂，如梧桐子大小，用白开水送服。
地榆丸
治疗脏毒兼夹湿气的情况。
白术（半两）、黄柏（炒制，二钱）、生地黄（二钱）、白芍药（二钱）、地榆（二钱）、黄芩（炒制，二钱）、香附（二钱）。共研为细末，用蒸饼作为粘合剂制成丸剂。
败毒散
治疗兼夹寒邪导致的便血。
羌活（一钱，去芦头）、独活（一钱，去芦头）、柴胡（一钱，去毛）、前胡（一钱，去芦头）、枳壳（炒制，八分）、茯苓（八分，去皮）、川芎（七分）、甘草（五分，蜜炙）、桔梗（八分，去芦头）。加生姜三片，水两钟，煎至一钟服用。
[Song] How to differentiate between Intestinal Wind (Changfeng) and Visceral Toxin (Zangdu)? It lies in whether there is retained cold or accumulated heat in the intestines and stomach. Turbid blood with a dark color indicates Visceral Toxin, caused by toxin accumulation within; clear and bright blood indicates Intestinal Wind, where external pathogens are expelled immediately upon contraction.
[Discussion] If a person's intestines and stomach are not deficient, pathogenic factors have no way to enter. Whether due to sitting or lying in wind-dampness, excessive drinking and full meals, sexual exhaustion, retention of raw/cold foods leading to cold stagnation, or accumulation of alcohol and food leading to heat, causing the nutritive blood to lose its proper course and seep into the meridians of the large intestine, this is how Intestinal Wind and Visceral Toxin arise. Therefore, when bleeding from the anus occurs suddenly accompanied by heat, the blood is clear and bright, and there is abdominal pain; if bleeding occurs over a long duration accompanied by cold, the blood is coagulated, turbid, and dark, with slight internal abdominal pain. Thus, sudden illness is called Intestinal Wind, meaning the pathogen enters from outside and manifests immediately upon contraction; onset after a long duration with turbid blood is called Visceral Toxin, meaning the toxin accumulates for a long time before manifesting. Those who bleed before defecating have bleeding close to the anus; those who bleed after defecating have bleeding far from the anus. The common saying of "before stool" or "after stool" is incorrect. If Visceral Toxin involves long-standing accumulated heat that suddenly presents with cold symptoms, it is actually not true cold, and one should not use hot-pungent medicines based on superficial cold signs.
Intestinal Wind
Zhu Danxi stated: Intestinal Wind originates solely in the Stomach and Large Intestine. If accompanied by Wind, herbs such as Cangzhu (Atractylodis Rhizoma), Qinjiao (Gentianae Macrophyllae Radix), and Xiangfu (Cyperi Rhizoma) may be used. For chronic hematochezia damaging blood and causing deficiency, or for Leprosy (Mafeng) and Tinea (Xuanchuang) appearing on the face, Chunpi Wan (Toona Sinensis Bark Pill) is indicated. Another prescription for Intestinal Wind with hematochezia uses Xiangfu (Cyperi Rhizoma) 1 liang, Zhike (Aurantii Fructus Immaturus) 7 qian, Chuanxiong (Ligustici Chuanxiong Rhizoma) and Danggui (Angelicae Sinensis Radix) each 5 qian, Huaijiao (Sophorae Tonkinensis Fructus) and Gancao (Glycyrrhizae Radix et Rhizoma) each 2 qian, decocted with Shengjiang (Zingiberis Rhizoma Recens) and Dazao (Jujubae Fructus).
Chunpi Wan
Treats deficiency caused by Intestinal Wind.
Guiban (Testudinis Carapax et Plastrum, 2 liang, roasted with su) Shengma (Cimicifugae Rhizoma, 5 qian) Xiangfu (Cyperi Rhizoma, 5 qian) Baishao (Paeoniae Radix Alba, 1.5 liang) Cebaiye (Platycladi Cacumen, 1 liang) Chunpigenbaipi (Toonae Radicis Cortex, 7.5 qian). Grind into powder, mix with congee to form pills the size of Sophora seeds. Take 60 pills per dose, delivered with a decoction made from Sini Tang (Four Substances Decoction) added with Baizhu (Atractylodis Macrocephalae Rhizoma), Huanglian (Coptidis Rhizoma), Gancao (Glycyrrhizae Radix et Rhizoma), and Chenpi (Citri Reticulatae Pericarpium) ground into powder.
Visceral Toxin
Cold and food toxins accumulate in the intestines and manifest only after a long time, called Visceral Toxin. For accumulated heat, Sanhuang Wan (Three Yellows Pill) is used. For dampness, Diyue Wan (Sanguisorbae Pill) is used. For cold, Baidu San (Detoxifying Powder) is used. Subsequently, Xionggui Tang (Chuanxiong and Danggui Decoction) is used to regulate according to cold or heat patterns. Add Fuling (Poria) and Huaihua (Sophorae Flos) for heat; add Muxiang (Aucklandiae Radix) and Fuling (Poria) for cold. (Formula see Headache section). For recovery, Sini Tang (Four Substances Decoction) is used with added Renshen (Ginseng Radix et Rhizoma), Huangqi (Astragali Radix), and Huaijiao (Sophorae Tonkinensis Fructus).
Sanhuang Wan
Treats hematochezia due to accumulated heat.
Cangzhu (Atractylodis Rhizoma, 1.5 liang) Chenpi (Citri Reticulatae Pericarpium, 1.5 liang) Huanglian (Coptidis Rhizoma, 7.5 qian) Lianqiao (Forsythiae Fructus, half liang). Grind into powder, mix with fresh Shengdi Huang (Rehmanniae Radix) pounded into paste to form pills the size of Sophora seeds. Take with plain warm water.
Diyue Wan
Treats Visceral Toxin complicated by dampness.
Baizhu (Atractylodis Macrocephalae Rhizoma, half liang) Huangbai (Phellodendri Cortex, stir-fried, 2 qian) Shengdi Huang (Rehmanniae Radix, 2 qian) Baishao (Paeoniae Radix Alba, 2 qian) Diyue (Sanguisorbae Radix, 2 qian) Huangqin (Scutellariae Radix, stir-fried, 2 qian) Xiangfu (Cyperi Rhizoma, 2 qian). Grind into powder, use steamed wheat cake as binder to form pills.
Baidu San
Treats hematochezia complicated by cold.
Qianghuo (Notopterygii Rhizoma et Radix, 1 qian, remove lu) Duhuo (Angelicae Pubescentis Radix, 1 qian, remove lu) Chaihu (Bupleuri Radix, 1 qian, remove mao) Qianhu (Peucedani Radix, 1 qian, remove lu) Zhike (Aurantii Fructus Immaturus, stir-fried, 8 fen) Fuling (Poria, 8 fen, remove skin) Chuanxiong (Ligustici Chuanxiong Rhizoma, 7 fen) Gancao (Glycyrrhizae Radix et Rhizoma, 5 fen, honey-roasted) Jiegeng (Platycodonis Radix, 8 fen, remove lu). Add 3 slices of Shengjiang (Zingiberis Rhizoma Recens), 2 zhong of water, decoct to 1 zhong and take.