Jaundice (yellowing of the skin), mania, black stools, and amnesia are all manifestations of Blood Stasis Syndrome (Xuè Xū Zhèng). Scholar Xu stated: If blood stasis is in the Upper Jiao, it leads to amnesia; if it is in the Lower Jiao, it leads to mania.

Cheng Wuji commented: When blood remains stagnant in the Lower Jiao and forms stasis, it is called Blood Stasis Syndrome. Generally, when treating Cold Damage (Shāng Hán), one should first observe the face and eyes, then the mouth and tongue, and finally palpate from the epigastrium down to the hypogastrium. If the hypogastrium is hard and full, and urination is difficult, this indicates retention of body fluids and can be treated with diuretics. If urination is normal, this is a Blood Stasis Syndrome, which can be treated with purgatives to remove blood stasis. In Yangming disease, if there is blood stasis accompanied by amnesia, the condition is severe, and Dǐdāng Tāng (Resisting Pill Decoction) should be used. In Taiyang disease, if heat binds to the Bladder causing symptoms resembling mania, the condition is milder, and Táorén Chéngqì Tāng (Peach Kernel Cathartic Decoction) should be used. The Classic states: If a patient presents with no exterior or interior excess signs, but has fever for seven to eight days, and although the pulse is floating and rapid, purgation may still be indicated. If purgation has been administered but the rapid pulse persists, stomach heat causes excessive hunger due to rapid digestion. By the sixth or seventh day, if there is no bowel movement, this indicates blood stasis, and Dǐdāng Tāng should be used. If the rapid pulse persists and diarrhea continues, it will likely result in bloody pus in the stool due to heat forcing blood downward. This syndrome typically occurs when there has been no bowel movement for six or seven days, yet without amnesia, mania, or hypogastric hardness. In such cases, Chengqi Decoctions are often used incorrectly. How do we know it is blood stasis? It is because the pulse is floating and rapid; floating indicates heat injuring Qi, and rapid indicates heat injuring Blood. If after purgation both floating and rapid pulses disappear, the disease resolves. However, if after purgation the rapid pulse disappears but the floating pulse remains, it means the heat in Ying Blood has cleared, but heat has merged into Wei Qi, causing hunger in the heart region. Pathogenic heat fails to digest food, leading to tidal fever and thirst. If after purgation the floating pulse disappears but the rapid pulse persists, it means heat in Wei Qi has cleared, merging with heat in Ying Blood. The combined heat forces blood downward. With deficient Stomach Qi and heat assisting digestion, there is excessive hunger. When blood reaches the Lower Jiao, if diarrhea continues, blood will be expelled, resulting in bloody pus. If there is no bowel movement for six or seven days, blood cannot exit, accumulates in the Lower Jiao as stasis, and must be purged with Dǐdāng Tāng. This represents an unusual treatment method for excess syndromes and reveals the subtlety of therapeutic principles.

In Taiyang disease lasting six or seven days, if exterior signs persist, the pulse is subtle and deep, and there is no chest binding, but the patient exhibits mania, it is because heat is stagnant in the Lower Jiao. The hypogastrium should be hard and full, and if urination is normal, bleeding will occur and the patient will recover. This happens because Taiyang pathogenic heat follows the meridian into the interior. Dǐdāng Tāng should be used. (Cheng Wuji commented: Taiyang Meridian corresponds to the Bladder Fu-organ. This is Taiyang heat following the meridian into the Fu. Six to seven days is when pathogenic qi transmits inward. A subtle and deep pulse indicates pathogenic qi in the interior. Exterior signs persisting suggests the pathogen is still shallow and should bind in the chest. If it does not bind in the chest but causes mania, the heat is bound in the Bladder. The Classic says "heat bound in the Bladder causes symptoms resembling mania"; here, actual mania indicates deeper heat. Hypogastric hardness and difficulty urinating indicate absence of blood stasis; normal urination confirms blood stasis. Dǐdāng Tāng is used to purge blood stasis. The phrase "persisting" implies the pathogen has not transmitted inward, nor is it shallow. The Bladder is the primary organ of Taiyang. "Heat in the Lower Jiao," "hypogastric hardness," and "normal urination" are all Bladder syndromes. Thus, it concludes "heat following the meridian binds in the interior." "In the interior" should be understood flexibly, referring not to the Three Yin organs, but to the interior of the Bladder via the meridian.)

In Taiyang disease, if the body is yellow, the pulse is deep and knotted, the hypogastrium is hard, and urination is difficult, there is no blood stasis. If urination is normal and the patient resembles mania, it is definitely blood stasis, and Dǐdāng Tāng should be used. (Body yellow, deep knotted pulse, hypogastric hardness, and difficult urination indicate stomach heat causing jaundice; Yīnchén Tāng (Artemisia Capillaris Decoction) may be given. Body yellow, deep knotted pulse, hypogastric hardness, normal urination, and resemblance to mania indicate heat bound in the Lower Jiao forming blood stasis, not stomach heat; Dǐdāng Tāng should be used to purge blood stasis.)

Dǐdāng Tāng Formula
Shuizhi (Leech, thirty pieces, processed) Mengchong (Dragonfly larva, thirty pieces, feet and wings removed, processed) Táorén (Peach Kernel, twenty pieces, skin and tips removed) Dàhuáng (Rhubarb Root and Rhizome, wine-soaked, three liang) These four ingredients are powdered. Boil in five sheng of water to obtain three sheng, strain, and take one sheng warm. If no effect, take another dose. (Bitter enters blood, salty overcomes blood. The salty and bitter nature of Mengchong and Shuizhi removes blood stasis. Sweet moderates knots, bitter drains heat. The sweet and bitter nature of Táorén and Dàhuáng purges knotting heat.) Human body possesses Qi and Blood. Qi belongs to Yang; stagnant Yang Qi disperses easily because Yang diseases are easier to treat. Blood belongs to Yin; stagnant Yin Blood is difficult to disperse because Yin diseases are harder to treat. Blood stagnating in the Lower Jiao requires potent toxic agents to overcome, hence the name Dǐdāng Tāng (Resisting/Overcoming Decoction). The Inner Canon states: Salty overcomes blood. Since blood stagnates in the Lower Jiao, salty flavor is primary; thus, Shuizhi (salty and cold) is the Sovereign herb. Bitter enters blood; since blood knots and does not move, bitter assists; thus, Mengchong (bitter and cold) is the Minister herb. The Liver is the source of blood; blood accumulation dries Liver Qi. The Liver dislikes urgency and prefers sweetness to moderate it. To scatter blood and moderate the Liver, Táorén (bitter, sweet, neutral) is the Assistant. Dàhuáng (bitter and cold) drains dampness below using bitterness; blood is also related to dampness. To cleanse blood and drive out heat, Dàhuáng is the Envoy. The combination of these four herbs can cure even severe toxic diseases.

In Cold Damage with heat, lower abdominal fullness usually implies difficult urination. If urination is now normal, there is blood stasis, which must be purged. Other medicines are not suitable; Dǐdāng Wán (Resisting Pill) should be used. (Cheng Wuji commented: Cold damage with heat and lower abdominal fullness indicates blood stasis in the Lower Jiao. If heat retains fluids causing obstruction, urination is difficult. If heat does not retain fluids but retains blood, urination is normal, confirming blood stasis. Táorén Chéngqì Tāng or Dǐdāng Tāng could be used. However, this case lacks body yellow, black stools, amnesia, or mania, indicating the condition is not severe. Thus, harsh purgatives are contraindicated. Dǐdāng Wán should be used in small doses. Note: Body yellow, black stools, amnesia, and mania are extensions of the theory. Based on the previous text, there is only fullness without hardness/pain.)

Dǐdāng Wán Formula
Shuizhi (twenty pieces) Mengchong (twenty-five pieces) Táorén (twenty pieces, skin and tips removed) Dàhuáng (three liang) These four ingredients are pounded and divided into four pills. Boil one pill in one sheng of water to obtain seven he. Take orally. Bleeding should occur at this time; if not, take another dose.

If Taiyang disease is unresolved and heat binds to the Bladder, causing symptoms resembling mania, if blood passes spontaneously, the patient recovers. If exterior signs remain, attack is premature; resolve the exterior first. Once the exterior is resolved, if only the hypogastrium feels urgent and knotted, attack may proceed with Táohé Chéngqì Tāng (Peach Pit Cathartic Decoction). (Note: Xījiǎo Dìhuáng Tāng (Rhino Horn and Rehmannia Decoction) treats upper jiao blood disorders like hematemesis or epistaxis. Táorén Chéngqì Tāng treats middle jiao blood disorders like blood stasis in the middle jiao or dysentery with pus/blood. Dǐdāng Tāng/Wán treats lower jiao blood disorders like mania due to blood stasis. The Upper, Middle, and Lower Jiao have specific indications. This passage should be read as three syndromes. "Recovers if blood passes" is one syndrome. There may be missing text. "Must resolve exterior first" is another syndrome. Mania indicates lower jiao blood, not Táorén Chéngqì Tāng syndrome. From "exterior resolved" to the end is a third syndrome, suggesting that spontaneous bleeding only clears lower jiao blood, while middle jiao blood remains due to distance, lingering in the hypogastrium. Also, Mengchong and Shuizhi in Dǐdāng formulas are fierce; combining Siwu Tang with wine-soaked Dàhuáng might be better, as noted in Bencao regarding Leech.)

Táohé Chéngqì Tāng Formula
Táorén (fifty pieces, skin and tips removed) Guìzhī (Cinnamon Twig, bark removed) Mangxiao (Mirabilite) Gāncǎo (Licorice Root, honey-fried, two liang each) Dàhuáng (four liang) These five ingredients are boiled in seven sheng of water to obtain two and a half sheng, strained, Mangxiao added, heated briefly until boiling, then removed from fire. Take five he warm before meals, three times daily. Mild laxation is expected. (Sweet moderates, pungent disperses. Hypogastric urgency is moderated by sweet Táorén. Lower jiao blood stasis is dispersed by pungent-hot Guìzhī. Cold is used to counteract heat; intense heat clots blood, so these two are added to Tiáowèi Chéngqì Tāng. Note: Analyzing these syndromes suggests Guìzhī (Twig) rather than Guìpí (Bark). Guìzhī is light and ascending, treating the upper; Guìpí is heavy and descending, treating the lower. Cheng's interpretation following the text is insufficient.)

Yangming disease patients who exhibit amnesia must have blood stasis. This is because they originally had long-standing blood stasis, causing amnesia. Although stools are hard, defecation is surprisingly easy, and the color is definitely black. Dǐdāng Tāng should be used to purge. (Cheng Wuji commented: The Inner Canon states: Blood pooling below causes confusion and amnesia. Long-standing blood stasis in the Lower Jiao causes amnesia. Low body fluids cause hard stools; with blood stasis inside, although stools are hard, defecation is easy, and color is black. Dǐdāng Tāng purges blood stasis.)

Haizang stated: Brown stool initially indicates severity; dark brown stool indicates greater severity; black stool indicates extreme severity. Color changes due to fire dryness. Like sheep blood in sunlight turning brown quickly, then black over time. Observe carefully. (Zhang Yuansu commented: Patient with no exterior/interior signs, fever for 7-8 days, floating rapid pulse can be purged. If purged and rapid pulse persists, stomach heat causes hunger. By day 6-7, no bowel movement indicates blood stasis, use Dǐdāng Tāng. If rapid pulse persists and bleeding continues, heat forces bloody pus.)

Cheng Wuji commented: During 6-7 days of constipation, without amnesia/mania or hypogastric hardness, how do we know it is blood stasis? Because the pulse is floating and rapid. Floating indicates heat in Qi, rapid indicates heat in Blood. After purgation, if both disappear, disease ends. If rapid disappears but floating remains, Ying heat clears, Wei heat remains, causing hunger and tidal fever/thirst. If floating disappears but rapid remains, Wei heat clears, Ying heat remains. Combined heat forces blood downward. Deficient Stomach heat aids digestion. Blood reaches Lower Jiao; if diarrhea continues, blood exits as pus. If no bowel movement for 6-7 days, blood accumulates in Lower Jiao as stasis, requiring Dǐdāng Tāng.

Zhang Yuansu asked: Purging requires no exterior signs and interior excess signs. Why purge if there are no exterior/interior signs and the pulse is floating/rapid? Answer: This is not Wind-Cold, but internal injury. No chills externally, no delirium internally, just fever for 7-8 days drying fluids, indicating excess Yang and deficient Yin. Without purging, heat persists and complications arise. Hence, purging is indicated despite floating/rapid pulse, without waiting for deep/solid pulse. Internal injury: Zúyáng pulse floating/rapid indicates Stomach/Spleen injury from improper purging. Zhang Zhongjing's intent aligns with this. All Cold Damage cases requiring purging involve pathogenic qi from Taiyang/Yangming meridians entering Fu organs. Here, it is not transmission from exterior to interior, but simply a case for purging, hence placed in Yangming chapter for study.

Patient with chest fullness, bloating, blue tongue, dry mouth desiring to rinse water but not swallow, no chills/fever, pulse slightly large and slow, abdomen not distended but patient claims fullness, indicates blood stasis. (Haizang: Rinsing water without swallowing, chest fullness, tenderness in epigastrium: Táorén Chéngqì Tāng.) Patient resembling heat syndrome, irritability, dry mouth/thirst, but pulse shows no heat, indicates hidden Yin, which is blood stasis; must purge.

Li Dongyuan's Pre-collection: Cold damage losing sweat leads to heat retaining in interior, transforming into blood. Amnesia and mania result. Blood reversing upward causes amnesia; blood accumulating downward causes internal urgency. Severe cases use Dǐdāng Tāng/Wán, Táorén Chéngqì Tāng, or Xījiǎo Dìhuáng Tāng until black material is expelled. Also: Use Dǐdāng formulas cautiously. Check for exterior signs. If blood stasis exists with unresolved exterior, do not use immediately; resolve exterior first with Guìzhī Tāng (Cinnamon Twig Decoction) because heat affects the Bladder/Taiyang.

Wu Kun stated: Blood stasis is retained internally. Cold damage in Taiyang requires sweating; failure to sweat causes internal blood stasis. Generally, check epigastrium, flanks, and hypogastrium for hardness/fullness/tenderness. Ask about urination. Difficult urination indicates water/Qi retention; normal urination indicates blood stasis.

Tao Hua stated: Palpate hypogastrium. Pain with normal urination, black stools, possibly jaundice, delirium, thirst, deep solid pulse indicates blood stasis. Táorén Chéngqì Tāng purges black material. If hypogastric fullness without hardness/pain and difficult urination, it is urinary retention; modify Wúlíng Sàn (Polyporus Powder) to promote urination gently to avoid fluid loss. If periumbilical hardness/pain, thirst, scanty red urine, hard stools indicate dry feces; Dàchéngqì Tāng (Major Cathartic Decoction) is needed.

Appendix:
Haizang stated: Ancient physicians varied drug potency but did not distinguish upper/lower locations. Now divided into Upper, Middle, Lower. Epistaxis, vomiting, spitting, hematemesis are Upper. Chest blood binding is Middle. Lower Jiao blood stasis is Lower. Drugs should match severity/location.
Excessive sweating causes epistaxis; pulse floating, moxa. Dry throat indicates spitting blood. Failure to sweat allows heat into interior causing vomiting/hematemesis (Upper). Treat with Xījiǎo Dìhuáng Tāng or Liánggé Sān (Cooling Grid Powder) plus Shēng Dìhuáng. Bleeding disorders generally do not involve thirst; Qi disorders do. This involves Foot Taiyin Spleen failing to control blood, leading to vomiting. Excess: Xījiǎo Dìhuáng Tāng; Deficiency: Huángqín Sháoyào Tāng (Scutellaria and Peony Decoction). Vomiting involves Spleen, hence Sháoyào is used.
Blood binding in chest: Head/body pain, rinsing water without swallowing, no heat, epistaxis. Chest fullness, rinsing water without swallowing, amnesia, coma, mania, epigastric tenderness: Blood in Middle. Táorén Chéngqì Tāng.
Lower Jiao blood stasis: Mania, hypogastric fullness/hardness, normal urination, black stools, umbilical pain: Dǐdāng Tāng/Wán. Resembling mania is Middle; actual mania is Lower. Same ingredients, different forms. Amnesia/mania/jaundice/black stools are severe; hypogastric fullness/normal urination is mild. Hence Decoction vs Pill. Pills use less potent ingredients (2/3 strength) for slower action. Decoction takes one sheng; Pill takes seven he.

Shēng Dìhuáng Tāng (Rehmannia Decoction)
For patients after 7-8 days with deep fine/subtle pulses, cold skin, umbilical fullness, mania/restlessness, hard black stools, normal urination: Blood stasis syndrome. For elderly/weak/qi-deficient patients, use this pill.
Shēng Dìhuáng (Fresh Rehmannia Juice one sheng; or dried two liang) Gānqī (Dry Lacquer, half liang, fried until smoke ceases) Shēng Ǒu (Fresh Lotus Root Juice half sheng; or Cìjì juice one and a half sheng) Lányè (Isatis Leaf, one handful chopped; or powder half sheng) Méngchong (Dragonfly larva, twenty pieces, wings/feet removed, fried in bran until yellow) Shuizhi (Leech, ten pieces, fried) Dàhuáng (Rhubarb, one liang, cut bean-sized) Táorén (Peach Kernel, crushed half liang) These eight ingredients are combined with three sheng of water, simmered slowly to two sheng, cooled, divided into two doses. Take first dose; if no blood passes after half a day, take second. This decoction is milder than Dǐdāng formulas. If Rehmannia/Lotus root juice unavailable, add water accordingly. Dǐdāng Wán may be too harsh, damaging blood; hence this formula is used.