桃仁（五十枚去皮尖） 桂枝（二两去皮） 甘草（二两炙） 大黄（四两） 芒硝（二两）
上五味以水七升煮取二升半去滓内芒硝更上火微沸下火先食温服五合日三服当微利
太阳病六七日表证犹存脉微而沉反不结胸其人如狂者以热在下焦少腹当硬满小便自利者下血乃愈所以然者以太阳随
经瘀热在腹里故也抵当汤主之
六七日经尽之期表证犹存脉微而沉已无表脉寸脉浮关脉沉当病结胸乃反不结胸而其人如狂者以热不在上焦而在下焦
也热结下焦其少腹必当硬满若是小便自利是热结血分下血乃愈以太阳表邪随经内入瘀热在里宜抵当汤水蛭虻虫桃仁大黄
破瘀而泄热也
大黄（三两酒浸） 水蛭（三十枚熬） 虻虫（三十枚熬去翅足） 桃仁（三十枚）
上四味为末水五升煮取三升去滓温服一升不下再服
太阳病身黄脉沉结少腹硬小便不利者为无血也小便自利其人如狂血证谛也抵当汤主之
身黄脉沉结少腹硬是皆血瘀之脉证血司于肝血结木郁贼伤己土则发黄色缘木主五色入土为黄故也然使小便不利则三
者乃膀胱湿热之瘀是茵陈五苓证非血证也小便自利其人如狂血证已谛故宜抵当
伤寒有热少腹满应小便不利今反利者为有血也当下之不可余药宜抵当丸
身有热而少腹满多是木郁阳陷疏泄不行应当小便不利今反利者是有血瘀当下然满而未硬下不必急减抵当之分两变汤
为丸缓攻可也
桃仁（五十枚，去皮及尖端） 桂枝（二两，去皮） 甘草（二两，蜜炙） 大黄（四两） 芒硝（二两）
以上五味药，用水七升，煎煮至剩余二升半，滤去药渣，加入芒硝，再次置于火上微沸即可。停药后，在进食前温服五合，每日服用三次，应当出现轻微腹泻。
太阳病（太阳经受邪所致的病证）经过六七天，表证仍然存在，脉象微而沉，反而没有形成结胸（水热互结于胸膈的病证），其人表现为如狂（神志失常，似狂非狂）的症状，这是因为热邪在下焦（人体下部脏腑区域）。少腹（下腹部）应当硬满，小便通畅自如的，通过泻下瘀血才能痊愈。之所以这样，是因为太阳经的邪气随经络内入，导致瘀热积聚在腹里，所以用抵当汤（破血逐瘀方剂）主治。
六七天是经气运行尽头的时期，表证依然存在，脉象微而沉，此时已无表证的脉象。寸脉浮、关脉沉时，应当发生结胸病，但反而没有结胸，而其人出现如狂的症状，这是因为热邪不在上焦（人体上部脏腑区域），而在下焦。热邪结聚在下焦，其少腹必然硬满。如果小便通畅自如，说明是热邪结聚在血分，只有排出瘀血才能痊愈。由于太阳表的邪气随经络内传入里，瘀热在体内，适宜用抵当汤（含水蛭、虻虫、桃仁、大黄）来破除瘀血并泄除热邪。
大黄（三两，酒浸） 水蛭（三十枚，熬制） 虻虫（三十枚，熬制，去掉翅膀和足） 桃仁（三十枚）
以上四味药研为末，用水五升，煎煮至剩余三升，滤去药渣，温服一升。如果服药后瘀血未下，再服用一次。
太阳病出现身黄、脉象沉结、少腹硬满、小便不利的，属于无瘀血的情况；小便通畅自如，其人如狂的，才是确凿的血证，用抵当汤主治。
身黄、脉沉结、少腹硬满，这些都是血瘀的脉证。血液由肝所主司，血结导致肝木郁滞，进而克制脾土（己土），从而引发黄疸。因为木对应五色，入土则呈现黄色。然而，如果小便不利，那么这三种症状就是膀胱湿热瘀阻的表现，属于茵陈五苓散证，而非血证。如果小便自利，其人如狂，血证已经确凿，所以适宜用抵当汤。
伤寒病有发热，少腹胀满，应当小便不利，现在反而小便通利的，是有瘀血的情况，应当攻下，不可使用其他药物，适宜用抵当丸。
身体有热且少腹胀满，多是肝木郁滞、阳气下陷、疏泄功能不行所致，应当出现小便不利。现在反而小便通利，说明是有瘀血，应当攻下。然而，虽然胀满但未硬实，攻下不必急切，减少抵当汤的分量，将汤剂改为丸剂，以缓攻为宜。
Tao Ren (Persicae Semen, fifty seeds, peeled and de-primed) Guizhi (Cinnamomi Ramulus, two liang, peeled) Gancao (Glycyrrhizae Radix et Rhizoma, two liang, honey-fried) Dahuang (Rhei Radix et Rhizoma, four liang) Mangxiao (Natrii Sulfas, two liang)
Take the above five ingredients, decoct with seven sheng of water until two and a half sheng remain, strain to remove dregs, add Mangxiao, heat again until it boils slightly. Remove from fire. Take five he of the warm decoction before meals, three times a day. A mild purgation is expected.
In Taiyang disease (disease pattern caused by pathogenic invasion of the Taiyang channel), after six or seven days, if exterior symptoms persist, the pulse is faint and deep, yet there is no formation of Jie Xiong (a syndrome characterized by fluid-heat accumulation in the chest/diaphragm). The patient exhibits a manic-like state (mental agitation resembling mania but not true madness). This is because the heat is located in the Lower Jiao (lower burner region). The lower abdomen should be hard and full. If urination is normal, the condition will resolve only after blood stasis is expelled. This occurs because the Taiyang pathogen has entered inward via the channels, causing stasis-heat to accumulate in the abdominal interior. Therefore, Didang Tang (Blood-Breaking Decoction) is indicated.
At the end of the six-to-seven-day cycle, when exterior symptoms persist and the pulse is faint and deep, the exterior pulse signs have disappeared. When the Cun (inch) pulse is floating and the Guan (bar) pulse is deep, Jie Xiong should occur. However, since Jie Xiong does not occur and the patient exhibits a manic-like state, the heat is not in the Upper Jiao (upper burner region) but in the Lower Jiao. Heat stagnating in the Lower Jiao causes hardness and fullness in the lower abdomen. If urination is free, it indicates that heat has congealed in the Blood aspect; only by expelling blood can the patient recover. Since the Taiyang exterior pathogen has entered inward along the channels, stasis-heat resides within the body. Didang Tang (containing Shuizhi, Mengchong, Tao Ren, and Dahuang) is suitable to break up stasis and drain heat.
Dahuang (Rhei Radix et Rhizoma, three liang, soaked in wine) Shuizhi (Hirudo, thirty pieces, processed) Mengchong (Oestrus, thirty pieces, processed, wings and feet removed) Tao Ren (Persicae Semen, thirty pieces)
Grind the above four ingredients into powder. Decoct with five sheng of water until three sheng remain. Strain. Take one sheng warm. If stool/blood is not passed, administer another dose.
In Taiyang disease, if there is yellowing of the skin, a deep and knotted pulse, hardness in the lower abdomen, and difficulty in urination, this indicates absence of blood stasis. If urination is free and the patient exhibits a manic-like state, this is a definitive Blood Syndrome (Xue Zheng), treated with Didang Tang.
Yellowing of the skin, deep and knotted pulse, and hardness in the lower abdomen are all pulse and symptom manifestations of blood stasis. Blood is governed by the Liver. Blood stasis leads to Liver Wood depression, which overacts on Spleen Earth (Ji Tu), resulting in jaundice. Wood corresponds to the five colors; entering Earth manifests as yellow. However, if urination is difficult, these three signs indicate damp-heat stasis in the Bladder, which belongs to Yinchen Wuling San syndrome, not a blood syndrome. If urination is free and the patient is manic-like, the blood syndrome is confirmed; thus, Didang Tang is appropriate.
In Shanghan (Cold Damage) with fever and fullness in the lower abdomen, urination should be difficult. Now, urination is free, indicating the presence of blood stasis. It must be purged. Other medicines are not suitable; Didang Wan (Blood-Breaking Pill) is indicated.
Fever with lower abdominal fullness usually results from Liver Wood depression and Yang sinking, leading to failure of dispersion and excretion, typically causing urinary difficulty. The fact that urination is now free indicates blood stasis requiring purgation. However, since there is fullness without hardness, urgent purgation is unnecessary. Reduce the dosage of Didang Tang and change the decoction into pills for a slow, gradual attack.