General Principle: Autumn is suitable for the purgative method. For conditions amenable to purgation, decoctions are more effective than pills and powders. Stop medication once the pathogen is addressed; there is no need to consume the entire dose.

In cases of diarrhea (Xialì), if the pulses at the cun, guan, and chi positions are all peaceful, but pressure on the epigastrium reveals hardness, urgent purgation is indicated. In cases of diarrhea with a slow and slippery pulse, indicating internal excess accumulation, purgation should be administered even if the diarrhea has not yet ceased. In Shaoyin disease, if dry mouth and throat appear within two to three days of onset, urgent purgation is indicated.

If Shaoyin disease persists for six or seven days accompanied by abdominal fullness and constipation, urgent purgation is indicated. When Yangming and Shaoyang diseases occur together, diarrhea is inevitable. If the pulse does not show signs of mutual overcoming (e.g., Wood overcoming Earth), it is termed "not losing" (bufu) and indicates a favorable prognosis. If signs of overcoming appear, it is termed "losing" (fu), indicating adverse progression. A slippery and rapid pulse indicates retained food stagnation, warranting purgation. It was asked: How can retained food stagnation be distinguished? The Master said: If the pulse at the cunkou position is floating and large, but feels rough upon pressure, and the chi position is also slightly rough, this indicates retained food stagnation, warranting purgation. Diarrhea accompanied by anorexia is due to retained food stagnation and warrants purgation. If diarrhea recurs at the same time of year, month, day, or hour after recovery, it is because the root cause remains unresolved, warranting purgation. If the pulse becomes slippery during diarrhea, it indicates that something needs to be removed; purgation will lead to recovery. A double-string-like and slow pulse indicates hardness in the epigastrium. A large and tight pulse indicates yin excess within a yang condition, making purgation appropriate.

In Yangming disease, delirium (shanyu) and tidal fever (chaore) accompanied by inability to eat indicate the presence of five or six dry fecal masses in the stomach. If the patient can eat, the stool is merely hard. If, two to three days after illness onset, the pulse is weak, without Taiyang or Shaoyang syndromes, but accompanied by irritability and epigastric stuffiness, even if the patient can eat by the fourth to fifth day, a small amount of Chengqi Tang should be given to mildly harmonize the stomach qi and provide slight relief. By the sixth day, administer one sheng of Chengqi Tang. If there is no bowel movement for six or seven days and urine output is low, although there is constipation, the stool may be hard at the beginning but loose at the end, indicating it has not fully hardened. Purgation at this stage will cause loose stools. One must wait until urination is normal and the stool is confirmed hard before proceeding with purgation.

In Yangming disease, a slow pulse despite sweating and absence of aversion to cold indicates heavy body sensation, shortness of breath, abdominal fullness, and wheezing. If tidal fever is present, the exterior syndrome is resolving, and interior attack is permissible. Continuous sweating on the hands and feet indicates hardened stool. In concurrent diseases of two yang channels (Taiyang and Yangming), if the Taiyang syndrome has resolved, presenting only with tidal fever, hand and foot sweating, difficult defecation, and delirium, purgation leads to cure. If the patient has difficulty urinating, intermittent difficulty and ease of defecation, occasional mild fever, wheezing, and inability to lie flat, dry fecal masses are present.

After severe purgation, if constipation persists for six or seven days with unrelenting irritability and abdominal fullness and pain, dry fecal masses are present. This occurs because retained food stagnation existed originally. These scenarios all fall under the indications for Dachengqi Tang.

In Yangming disease, fever with profuse sweating requires urgent purgation. After Shanghan, a deep and forceful pulse indicates internal excess, resolvable by purgation. If Taiyang disease is unresolved and the pulse at both yin and yang positions ceases temporarily, chills followed by sweating indicate resolution. However, if the chi pulse is excess, purgation resolves the condition.

If a patient lacks typical exterior or interior syndromes but has had fever for seven to eight days with a floating and rapid pulse, purgation may still be applied. In Shanghan, if fever and sweating do not resolve the condition, accompanied by epigastric stuffiness, vomiting, and diarrhea, after ten-plus days with heat binding internally and alternating chills and fever, these scenarios belong to the indications for Xiaochaihu Tang.

In Shaoyin disease, purging clear water of pure green color, accompanied by epigastric pain and dry mouth/throat, warrants purgation. Abdominal fullness and pain indicate excess, requiring purgation. Persistent abdominal fullness that does not significantly relieve warrants purgation. In Shanghan, after six or seven days, unclear vision, dull eyes, absence of obvious exterior/interior syndromes, difficult defecation, and mild fever indicate excess, requiring urgent purgation. Sweating with delirium indicates dry fecal masses in the stomach due to wind-heat entering the interior. Purgation should be performed only after the exterior syndrome has passed (guojing). Premature purgation causes speech confusion due to exterior deficiency and interior excess. Cure follows purgation.

Irritability and fever resolving with sweating resemble malaria. Evening fever belongs to Yangming disease. An excess pulse warrants purgation. These scenarios belong to the indications for Xiaochaihu Tang and Dachengqi Tang.

Diarrhea with delirium indicates dry fecal masses. In Yangming disease, profuse sweating depletes fluids, drying the stomach and hardening the stool, leading to delirium. These scenarios belong to the indications for Xiaochengqi Tang.

In Yangming disease, a slow pulse with sweating but no aversion to cold, heavy body, shortness of breath, abdominal fullness, wheezing, and tidal fever indicate resolving exterior and permissible interior attack. Continuous hand and foot sweating indicates hardened stool; Dachengqi Tang is the primary formula. If sweating is profuse with mild fever and aversion to cold, the exterior is unresolved; Guizhi Tang is indicated. If fever is not tidal, Chengqi Tang is contraindicated. If abdominal fullness and obstruction are severe, Xiaochengqi Tang may be given to mildly harmonize stomach qi without causing severe diarrhea.

In Yangming disease, tidal fever with slightly hard stool allows for Dachengqi Tang; if not hard, it is contraindicated. If no bowel movement for six or seven days and concern exists for dry fecal masses, administer a small amount of Xiaochengqi Tang as a test. If gas passes after ingestion, dry fecal masses are present, and purgation is permissible. If no gas passes, the stool is hard initially but loose later; purgation is contraindicated as it causes abdominal fullness and anorexia. Thirst satisfied by water may cause hiccups. Subsequent fever indicates recurrent hard stool in small amounts; Xiaochengqi Tang should harmonize. Absence of gas passage strictly contraindicates purgation.

In Yangming disease, delirium with tidal fever and a slippery, rapid pulse indicates Xiaochengqi Tang. After administering one sheng of Chengqi Tang, if gas passes, another sheng may be given; if not, do not repeat. If the next day shows no bowel movement and the pulse becomes slightly rough and sluggish, interior deficiency exists, making treatment difficult; Chengqi Tang is contraindicated.

Yangming disease with mental agitation without prior emesis or purgation falls under the indications for Wei Chengqi Tang.

In Taiyang disease, if heat binds to the Bladder, causing manic behavior, spontaneous bleeding resolves the condition. If the exterior remains unresolved, exterior release must precede interior attack. Once the exterior is resolved, if only lower abdominal urgency and binding remain, purgation is permissible using Taohe Chengqi Tang.

In Taiyang disease, after six or seven days, if the exterior syndrome persists but the pulse is subtle and sinking without forming Jie Xiong, and the patient exhibits mania due to heat in the lower jiao with lower abdominal hardness/fullness but normal urination, bloodletting/purging blood resolves the condition. This is because Taiyang pathogens follow the meridians into the interior, creating blood-heat stasis. Purging is indicated.

In Taiyang disease, jaundice with a sinking, knotted pulse, lower abdominal hardness/fullness, and urinary difficulty indicates absence of blood stasis (likely damp-heat jaundice). Normal urination with manic behavior indicates blood retention. In Yangming disease, forgetfulness indicates blood retention due to long-standing blood stasis. Although stool may be hard, it is easy to pass and black in color. These scenarios belong to the indications for Dandang Tang.

In Shanghan with fever, lower abdominal fullness usually implies urinary difficulty. If urination is normal, blood stasis is present, requiring purgation with Dandang Wan.

In Yangming disease, fever and sweating indicate heat dispersing outward, preventing jaundice. If only the head sweats, sweat stops at the neck, urination is difficult, and thirst for fluids exists, blood-heat in the interior causes jaundice. Purging with Yinchenhao Tang is indicated.

After seven or eight days of Shanghan, orange-colored jaundice, urinary difficulty, and mild abdominal fullness also fall under Yinchenhao Tang indications.

Jie Xiong without significant heat indicates water-fluid binding in the chest and hypochondrium. Only slight head sweating in Shanghan after six or seven days, with Jie Xiong heat-excess syndrome, sinking-tight pulse, epigastric pain, and stone-hard palpation, belongs to Daxiexiong Tang indications. Jie Xiong with neck stiffness resembling Rou Jing resolves with purgation (Daxiexiong Wan).

In Taiyang Wind Strike with diarrhea and vomiting, purgation is permissible only after exterior resolution. Profuse sweating occurring intermittently, headache, epigastric stuffiness/fullness radiating to the hypochondrium, dry retching with shortness of breath, sweating without aversion to cold, indicates resolved exterior and unharmonized interior, falling under Shizao Tang indications.

Wu Keji stated: In Taiyang disease, if fever and sweating do not resolve and steaming fever occurs, it belongs to Stomach excess; Wei Chengqi Tang purges it. For tidal fever and abdominal pain, Xiaochaihu Tang plus Houpo purges it. In Yangming disease, profuse sweating dries the stomach and hardens stool, causing delirium; Xiaochengqi Tang is used. With delirium, slippery-rapid pulse, and tidal fever, Xiaochaihu Tang is used. With delirium, tidal fever, and anorexia, five or six dry fecal masses exist in the stomach; Xiaochengqi Tang is used. If eating is possible and stool is hard, Dachengqi Tang is used. With sweating and delirium, dry fecal masses exist; Wei Chengqi Tang is used. With tidal fever, continuous hand/foot sweating, difficult defecation, and delirium, Dachengqi Tang is used. After five to six days of constipation with periumbilical pain and intermittent irritability, dry fecal masses exist; Wei Chengqi Tang is used. After previous purgation, if six to seven days pass with constipation, unrelenting irritability, and abdominal pain, dry fecal masses exist; Dachengqi Tang is used. With urinary difficulty, intermittent stool consistency, mild fever, wheezing, and inability to lie flat, dry fecal masses exist; Dachengqi Tang is used. After vomiting with abdominal fullness, Wei Chengqi Tang is used. After sweating, vomiting, or purgation with mild irritability, frequent urination, and hard stool, Xiaochengqi Tang is used. For persistent abdominal fullness, Xiaochengqi Tang is used. For diarrhea with slippery-rapid pulse indicating retained food, Xiaochengqi Tang is used. For abdominal fullness/pain indicating retained food, Xiaochengqi Tang is used. For deep-forceful pulse, internal excess, and unrelenting tidal fever, Xiaochaihu Tang is used.

Generally, purgatives require a deep, solid, slippery, or rapid-forceful pulse. Palpation revealing hardness or tenderness confirms the indication. If purgation fails, re-palpate; if hardness persists, purge again. If the abdomen becomes soft and pulse weak post-purgation, deficiency exists; Shenhu Sanbai Tang harmonizes. If fever, tidal fever, or alternating chills/fever persist, Xiaochaihu Tang modifies harmonize. If irritability prevents sleep, Zhuyeshigu Tang or Shiwei Wendan Tang is used.

The Huoren Shu states: Interior Shanghan syndromes require assessing heat depth. Zhang Zhongjing prescribed purgatives like Dachengqi Tang, Shizao Tang, and Xiaochaihu Tang for severe cases, and Wei Chengqi Tang, Pi Yue Wan, or small doses of Xiaochengqi Tang to mildly harmonize the stomach for milder cases. Deficient patients should receive ten parts tonification to one part purgation; robust excess patients may be purged; mixed deficiency/excess should avoid severe purgation. This is from the Jin Gui Yao Lue. Wang Shuhe warned against improper Chengqi Tang use in his Shanghan preface.

Li Dongyuan ranked formulas by urgency: Dachengqi Tang is most urgent, followed by Xiaochengqi Tang, then Wei Chengqi Tang, then Xiaochaihu Tang.

Wang Haicang stated: Dachengqi Tang treats severe excess and fullness. Fullness presents as chest/abdominal distension like joined tiles; excess presents as constipation. It is used when Pi, Man, Zao, and Shi syndromes coexist. For miscellaneous diseases, it is adjusted dynamically. Da Huang treats severe excess; Mang Xiao treats severe dryness (these two treat tangible blood stasis). Hou Po treats severe fullness; Zhishi treats Pi (these two treat intangible qi stagnation).

Xiaochengqi Tang treats Pi and Shi with mild fullness, resembling satiety without gas passage. It is Dachengqi Tang minus Mang Xiao. Used for epigastric Pi, open but difficult defecation, high heat requiring purgation. Wei Chengqi Tang treats Shi without Man, resembling an inverted tile, with gas passage, dry feces, constipation, and delirium. These three methods must not be confused; error leads to harm. Using Dachengqi for Wei Chengqi indications exhausts yuan qi due to qi-moving herbs. Using Wei Chengqi for Dachengqi indications causes mental cloudiness due to lack of qi-moving herbs. Using Mang Xiao for Xiaochengqi indications causes excessive diarrhea and deficiency.

Li Dongyuan further clarified: Sanyi Chengqi Tang differentiates excess for purgation. Adjust dosage based on urgency. Non-aversion to cold, preference for heat, thirst, delirium, abdominal fullness/wheezing, and continuous hand/foot sweating require urgent Dachengqi Tang. If pathogen is shallow with suspected dry feces and lower abdominal pain, test with Xiaochengqi Tang. Gas passage confirms dry feces for purgation. No gas passage indicates initial hardness/later looseness; purgation causes fullness/anorexia. If obstruction persists, give Xiaochengqi Tang to mildly harmonize stomach qi without severe purgation. Post-sweating non-aversion to cold with interior excess requires Wei Chengqi Tang to harmonize stomach qi.

Cheng Wuji stated: Severe heat and firm excess warrant Dachengqi Tang. Mild heat and slight excess warrant Xiaochengqi Tang, removing Mang Xiao from Dachengqi due to less severe heat, and reducing Hou Po/Zhishi due to less firmness. If heat is severe but firmness is not extreme, use a mild agent: Dachengqi Tang minus Hou Po/Zhishi plus Gancao to harmonize stomach. Using Wei Chengqi for Dachengqi indications fails to subdue pathogens; using Dachengqi for Xiaochengqi indications damages healthy qi, causing fullness/anorexia, hence the warning against severe purgation. Zhang Zhongjing separated treatments to adhere to sage principles. Later physicians merged these three formulas, claiming universal efficacy for Shanghan and miscellaneous diseases, contradicting Zhang Zhongjing and the Yellow Emperor's principles of urgency. This confusion harms patients. Those with impartial judgment should seek truth in the Nei Jing and Zhang Zhongjing's formulas, ensuring symptom-formula correspondence, to discern authenticity.

Wang Haicang further stated: In Shanghan, if exterior symptoms suggest purgation but the pulse is fine and unsuitable for purgation, Xixin Tang is primary. With a forceful pulse, Huanglian Xixin Tang is used; with a weak pulse, Banxia Xixin Tang is used.