治血结胸中，手不可近，或中焦蓄血，寒热，胸满，漱水不欲咽，善忘，昏迷，如狂者。
此
桃仁（半两） 大黄（一两） 硝（三钱） 桂（三钱） 甘草（三钱）
上每服一两，姜、水煎服。
治伤寒蓄血，并治症瘕，追虫、攻毒甚佳。
水蛭（熬） 虻虫（去翅足，各三十枚） 桃仁（二十枚） 大黄（三两，酒洗）
上四味，水五升，煮取三升，去滓，温服一升。不下再服，即以四味捣粉为丸，分四丸，
以
柯韵伯曰∶膀胱为水府，血本无所容蓄者也。然太阳为诸阳主气，是气之最多者，而其
经
热结
必其
急
沉
便
非至峻之剂，不足以抵其巢穴而当此重任，故立抵当汤。蛭，虫之善饮血者，而利于水；虻
，虫之善吮血者，而猛于陆。并举水陆之善取血者以攻之，同气相求；更佐桃仁之苦甘，推
陈致新，大黄苦寒，荡涤邪热，此名抵当也。若热虽盛而未狂，小腹满而未硬，宜小其制，
为丸以缓治之。若外症已解，小腹急结，其人如狂，是转属阳明，用调胃承气加桃仁、桂枝
之行血者于其中，以微利之，胃和则愈矣。此桃仁承气，又为治之缓也。
治伤寒五六日，寒热往来，胸胁苦满，嘿嘿不欲饮食，心烦，喜呕，耳聋，脉数。此是
少阳
柴胡（半斤） 黄芩 人参 甘草（各三两） 半夏（半升） 生姜（三两） 大枣
（十二枚）
上七味，以水一斗二升，煮取六升，去滓，再煎取三升，温服一升，日三服。若胸中烦
而不
根四
便不
咳者，
程郊倩曰∶方以小柴胡名者，配乎少阳而取义。至于制方之旨及加减法，则所云上焦得
通，
入里
故
故
其余或之云者，以少阳在人身为游部，凡表里经络之罅，皆能随其虚而见之，不定之邪也。
据症皆是太阳经中所有者，特以五六日上见，故属之少阳。半表半里兼而有之，方是小柴胡
症。方中柴胡以疏木，使半表之邪得从外宣；黄芩清火，使半里之邪得从内彻；半夏能开结
痰，豁浊气以还清；人参能补久虚，滋肺金以融木；甘草和之，而更加姜、枣助少阳生发之
气，使邪无内向也。至若烦而不呕者，火成燥实而逼胸，故去人参、半夏，加栝蒌实。渴者，
燥已耗液而逼肺，故去半夏，加栝蒌根。腹中痛，木气散入土中，胃阳受困，故去黄芩以
安土，加芍药以戢木。胁下痞硬者，邪既留则木气实，故去大枣之甘而缓，加牡蛎之咸而软
也。心下悸，小便不利者，土被侵则木气逆，故去黄芩之苦而伐，加茯苓之淡而渗也。不渴
，身有微热者，半表之寒尚滞于肌，故去人参，加桂枝以解之。咳者，半表之寒凑入于肺，
故去参、枣，加五味子，易生姜为干姜以温之，虽肺寒不减黄芩，恐木寡于畏也。总之，邪
在
治疗血瘀结聚于胸中，疼痛剧烈至手不可触碰；或中焦蓄积瘀血，伴有寒热交替、胸部胀满、口干想含水漱口但不愿咽下、容易健忘、神志昏迷、似狂非狂的症状。
此方由以下药材组成：
桃仁（半两） 大黄（一两） 芒硝（三钱） 桂枝（三钱） 甘草（三钱）
以上药物，每次服用一两，加生姜和水煎煮后服用。
治疗伤寒导致的蓄血证，并治疗症瘕（腹内结块），在驱虫、攻毒方面效果极佳。
水蛭（烫制） 虻虫（去除翅足，各三十枚） 桃仁（二十枚） 大黄（三两，用酒清洗）
以上四味药，用水五升，煮取三升药液，滤去药渣，温服一升。若服药后瘀血未下，可再服一次；若仍不下，可将这四味药捣碎制成丸剂，分为四丸服用。
柯韵伯说：膀胱是水液汇聚之所，血液本不应在此处蓄积。然而太阳经统摄诸阳之气，是阳气最旺盛的经脉，其经脉中的热邪结聚，必然导致严重的病理变化。必须使用药性峻猛的方剂，才足以深入病所（巢穴）并承担此重任，因此创立了抵当汤。水蛭是善于吸食血液的水生昆虫，且利于在水中活动；虻虫是善于吮吸血液的陆生昆虫，且凶猛于陆地。同时使用水陆两种善于取血的昆虫来攻击瘀血，这是同气相求的原理；更佐以桃仁的苦甘之性，推陈出新；大黄苦寒，荡涤邪热，这就是名为“抵当”的原因。如果热势虽盛但尚未出现狂躁，小腹部胀满但未变硬，应当减小剂量，制成丸剂以缓和的方式治疗。如果外感症状已经解除，小腹部急迫结聚，患者神志如狂，这是病邪转入阳明经，使用调胃承气汤加入桃仁、桂枝等行血药物在其中，以轻微通下的方式治疗，胃气调和则痊愈。这桃仁承气汤，又是更为缓和的治疗方法。
治疗伤寒五六日后，出现寒热往来（忽冷忽热）、胸胁部苦闷胀满、神情沉默不欲饮食、心烦、喜欢呕吐、耳聋、脉象数动。这是少阳病（少阳经受邪所致的病证）。
柴胡（半斤） 黄芩 人参 甘草（各三两） 半夏（半升） 生姜（三两） 大枣（十二枚）
以上七味药，用水一斗二升，煮取六升药液，滤去药渣，再次煎煮取三升药液，温服一升，每日三次。如果胸中烦闷而不……（原文此处有残缺）根四便不咳者……（原文此处有残缺）
程郊倩说：方剂命名为小柴胡汤，是因为配伍符合少阳经的特性而取其义。至于制方的宗旨及加减方法，就是前面所说的上焦得通……（原文此处有残缺）入里……（原文此处有残缺）故……（原文此处有残缺）故……（原文此处有残缺）其余所谓的情况，是因为少阳在人体中属于游移不定之部，凡是表里经络的空隙之处，都能随着正气虚弱而出现病症，这是不定的邪气。根据症状来看，这些都是太阳经中原本存在的症状，特别因为是在发病五六日后出现，所以归属于少阳。半表半里兼而有之，这才是小柴胡汤证。方中柴胡用来疏泄肝胆木气，使半表之邪得以从外部宣散；黄芩清泻火邪，使半里之邪得以从内部透达；半夏能开通凝结之痰，豁除浊气以恢复清明；人参能补益久虚之体，滋养肺金以融合木气；甘草调和诸药，再加上生姜、大枣助长少阳生发之气，使邪气没有向内侵袭的路径。至于如果烦闷但不呕吐，是因为火邪形成燥实而逼迫胸膈，所以去掉人参、半夏，加入栝蒌实。口渴的，是因为燥热已耗伤津液而逼迫肺脏，所以去掉半夏，加入栝蒌根。腹中疼痛，是因为木气散入脾土之中，胃阳受困，所以去掉黄芩以安顿脾土，加入芍药以收敛木气。胁下痞塞坚硬，是因为邪气停留则木气实盛，所以去掉大枣的甘缓之性，加入牡蛎的咸软之性。心下悸动，小便不利的，是因为脾土被侵犯则木气逆乱，所以去掉黄芩的苦寒伐性，加入茯苓的淡渗利湿之性。不口渴，身体有微热的，是因为半表的寒邪尚滞留于肌表，所以去掉人参，加入桂枝以解表。咳嗽的，是因为半表的寒邪凑入于肺脏，所以去掉人参、大枣，加入五味子，将生姜改为干姜以温肺，虽然肺寒但不减去黄芩，恐怕木气缺乏制约。总之，邪气在……（原文此处有残缺）
Treats blood stasis congealed in the chest, so painful that it cannot be touched by hand; or blood accumulation in the middle jiao (middle burner), accompanied by alternating chills and fever, chest fullness, a desire to rinse the mouth with water but no desire to swallow, frequent forgetfulness, coma, and a manic-like state.
This formula consists of:
Tao Ren (Persicae Semen, 0.5 liang) Da Huang (Rhei Radix et Rhizoma, 1 liang) Xiao Ming (Natrii Sulfas, 3 qian) Gui Zhi (Cinnamomi Ramulus, 3 qian) Gan Cao (Glycyrrhizae Radix et Rhizoma, 3 qian)
For each dose of one liang, decoct with fresh ginger and water, and take orally.
Treats blood accumulation caused by Shanghan (Cold Damage disease); also treats Zheng Jia (abdominal masses), and is excellent for expelling parasites and attacking toxins.
Shui Zhi (Hirudo, scalded) Meng Chong (Ophryogenia, wings and feet removed, 30 each) Tao Ren (Persicae Semen, 20 pieces) Da Huang (Rhei Radix et Rhizoma, 3 liang, washed with wine)
Take the above four ingredients, add five sheng of water, boil to obtain three sheng of liquid, remove the dregs, and take one sheng warm. If the blood is not expelled, take another dose. If still not expelled, crush these four ingredients into powder and make pills, divided into four pills.
Ke Yunbo said: The Bladder is the residence of water, and blood should not accumulate there. However, the Taiyang (Greater Yang) channel governs all yang qi and is where qi is most abundant. Heat binding in its channels inevitably leads to severe pathological changes. Only potent agents are sufficient to reach the nest of the pathogen and shoulder this heavy responsibility; therefore, Didang Tang was established. Shui Zhi is an insect good at drinking blood and advantageous in water; Meng Chong is an insect good at sucking blood and fierce on land. By combining water-dwelling and land-dwelling insects skilled at taking blood to attack the stasis, we follow the principle of "like attracts like." Furthermore, assisted by the bitter-sweet nature of Tao Ren to push out the old and generate the new, and the bitter-cold Da Huang to cleanse evil heat, this is why it is named "Didang" (meaning "to resist/attack directly"). If the heat is severe but there is no mania, and the lower abdomen is full but not hard, the dosage should be reduced, and pills should be made for slow treatment. If external symptoms have resolved, the lower abdomen is urgent and knotted, and the person is manic-like, the pathogen has transferred to the Yangming (Yang Brightness) channel. Use Tiaowei Chengqi Tang added with Tao Ren and Gui Zhi (blood-moving herbs) within it, to slightly promote purgation. When the Stomach qi harmonizes, the patient recovers. This Taoren Chengqi Tang is an even milder method of treatment.
Treats Shanghan after five or six days, presenting with alternating chills and fever, bitter distension in the chest and hypochondrium, silent desire not to eat, mental irritability, frequent vomiting, deafness, and rapid pulse. This is Shaoyang disease (disease of the Shaoyang channel).
Chai Hu (Bupleuri Radix, 8 liang) Huang Qin (Scutellariae Radix) Ren Shen (Ginseng Radix) Gan Cao (Glycyrrhizae Radix et Rhizoma) [each 3 liang] Ban Xia (Pinelliae Rhizoma, 0.5 sheng) Sheng Jiang (Zingiberis Rhizoma Recens, 3 liang) Da Zao (Jujubae Fructus, 12 pieces)
Take the above seven ingredients, add twelve dou of water, boil to obtain six dou of liquid, remove the dregs, and decoct again to obtain three dou of liquid. Take one dou warm, three times a day. If there is vexation in the chest without... [text missing] ...root four stools not... [text missing] ...cougher... [text missing]
Cheng Jiaoqian said: The formula is named Xiao Chai Hu Tang because its composition aligns with the Shaoyang channel and derives its meaning from it. Regarding the principles of formula construction and modification methods, as mentioned earlier, when the Upper Jiao (Upper Burner) becomes unblocked... [text missing] entering the interior... [text missing] therefore... [text missing] therefore... [text missing]. The remaining cases mentioned occur because Shaoyang in the human body is a migratory region; any gaps in the exterior-interior meridians can manifest diseases following deficiency, representing unpredictable pathogens. Based on symptoms, these are conditions originally present in the Taiyang channel, but specifically appearing after five or six days, thus attributed to Shaoyang. Having both half-exterior and half-interior characteristics constitutes the Xiao Chai Hu Tang syndrome. In the formula, Chai Hu soothes the Wood qi, allowing half-exterior pathogens to be dispersed externally; Huang Qin clears fire, allowing half-interior pathogens to penetrate internally; Ban Xia opens condensed phlegm, clearing turbid qi to restore clarity; Ren Shen tonifies long-standing deficiency, nourishing Lung Metal to merge with Wood; Gan Cao harmonizes, further aided by Sheng Jiang and Da Zao to assist the generating qi of Shaoyang, preventing pathogens from moving inward. As for vexation without vomiting, fire has formed dryness and solidity pressing on the chest, so Ren Shen and Ban Xia are removed, and Gua Lou Shi (Trichosanthis Fructus) is added. For thirst, dryness has consumed fluids and pressed on the Lungs, so Ban Xia is removed and Gua Lou Gen (Trichosanthis Radix) is added. For abdominal pain, Wood qi has scattered into Earth, confining Stomach Yang, so Huang Qin is removed to settle Earth, and Shao Yao (Paeoniae Radix Alba) is added to restrain Wood. For subcostal stuffiness and hardness, since pathogens remain, Wood qi is excessive, so the sweet and slowing Da Zao is removed, and Mu Li (Ostrea Shell) is added for its salty and softening properties. For epigastric palpitations and difficult urination, Earth is invaded causing Wood qi to rebel, so the bitter and draining Huang Qin is removed, and Fu Ling (Poria) is added for its bland and diuretic properties. For no thirst and slight body heat, half-exterior cold still stagnates in the muscles, so Ren Shen is removed and Gui Zhi is added to resolve it. For cough, half-exterior cold gathers in the Lungs, so Ren Shen and Da Zao are removed, Wu Wei Zi (Schisandrae Fructus) is added, Sheng Jiang is replaced with Gan Jiang (Zingiberis Rhizoma) to warm, and although Lung cold exists, Huang Qin is not reduced, lest Wood lack restraint. In short, when the pathogen is in... [text missing]