Wang Haogu (styled Haicang) stated: It is true that people have established methods for treating Shanghan (Cold Damage) and formulas for treating Zabo (Miscellaneous Diseases). However, this is not the complete truth. I assert that there are also formulas for treating Shanghan and methods for treating Zabo. "Formula" is essentially "method"; how can they be different? The key lies in comprehensively understanding the differentiation of meridians, exterior-interior relationships, and zang-fu organs. How could there be two separate principles? Because the intellectual capacity of later generations did not match that of the ancients, Shanghan and Zabo were divided into two categories. Consequently, some practitioners excel in one area but lack proficiency in the other. When the state selected officials by dividing them into seven departments, it likely led to scholarship becoming increasingly narrow and specialization becoming increasingly crude.

Let us discuss the two categories of Shanghan and Zabo. Shanghan enters from the exterior to the interior; the method should first treat the exterior pathogen and then the interior syndrome. Zabo originates from the interior and manifests externally; the method should first treat the internal organs and then address the external manifestations. As for conditions where the interior and exterior do not affect each other, one should primarily treat the main disease. The method remains the same. Why must they be divided into two? Generally, the external manifestations of Zabo are not separated from the Exterior (Biao), and the internal pathology of Shanghan is not separated from the Interior (Li). For conditions in the Exterior, sweating methods are used; for conditions in the Interior, purgative methods are used; for conditions in the Middle Jiao, harmonizing methods are used. This is an unchangeable principle. The cold, heat, warm, and cool properties of medicines are contained within these methods.

Dai stated: In Shanghan Zabo, there are correct Shanghan diseases and Shanghan with mixed miscellaneous diseases. For mixed diseases difficult to treat with standard Shanghan methods, if patient symptoms vary, presenting both cold and heat signs clearly visible, one should first address the major aspects among them, and subsequently treat the remaining symptoms slowly. However, one must not use exclusively hot or exclusively cold formulas. For example, if a patient presents with vomiting, thirst, irritability, and fever, and after administering Xiao Chaihu Tang (Minor Bupleurum Decoction), these symptoms cease but diarrhea persists, saying Xiao Chaihu Tang is incorrect contradicts the cessation of vomiting and thirst; saying it is correct contradicts the persistence of diarrhea. Similarly, if a patient presents with vomiting, diarrhea, and cold extremities, and after administering Jiang Fu Tang (Ginger and Aconite Decoction), these symptoms cease but fever, thirst, delirium, and unconsciousness appear, saying Jiang Fu Tang is incorrect contradicts the cessation of vomiting and diarrhea; saying it is correct contradicts the appearance of fever and delirium. This illustrates that although Shanghan mixed diseases may not show obvious simultaneous cold and heat signs as described previously, yin contains yang and yang contains yin, lying latent within and not immediately manifesting. If medication is biased, one aspect will decline while the other becomes excessive. Physicians must repeatedly examine and recognize conditions at points of doubt, avoiding focusing on one aspect while neglecting another, to achieve perfection.

Among the Three Yang syndromes, there are Combined Yang syndromes and Pure Yang syndromes. Among the Three Yin syndromes, there are Excessive Yin syndromes and Pure Yin syndromes. "Combined Yang" refers to what the classics call "He Bing" (Combined Disease). "Pure Yang" refers to what the classics describe as "pulse both yin and yang positions are full and large, sweating does not resolve the condition, death ensues," and also "in cases of sweating or taking herbal decoctions, some fail to sweat and die; this is because yang heat is extreme and yin qi is exhausted, thus unable to produce sweat." Both situations involve yang without yin, hence called "Pure Yang." An "Excessive Yin" case in the Three Yin involves Shaoyin disease with body pain, cold hands and feet, bone and joint pain, and a deep pulse, treated with Fuzi Tang (Aconite Decoction). Cold hands, body pain, and deep pulse indicate cold excess in the yin. A "Pure Yin" case involves Shaoyin disease with aversion to cold, curled-up posture, diarrhea, and cold extremities extending upwards, which is untreatable, termed "no yang." If cold pathogens lodge in the Three Yin meridians, extreme cold generates heat, transmitting to the Yangming stage. Pathogens lodging in the Three Yin are generally cold, so warming and sweating methods are appropriate; if extreme cold transforms into heat, cold purgatives are appropriate. Generally, the Three Yin and Three Yang can all directly receive pathogens, not just transmitting from the Taiyang meridian. Thus, the classics state: "Yangming resides in the center, belonging to Earth, the destination of all things, where transmission ceases." For instance, if Taiyang pathogens enter the stomach, they do not transmit to Yangming; if Yangming pathogens enter the stomach, they do not transmit to Shaoyang; if Shaoyang pathogens enter the stomach, they do not transmit to the Three Yin. If Three Yin pathogens directly receive pathogens, transform into heat, and enter the stomach, the classics state: "Shanghan with floating and slow pulse, warm hands and feet naturally, relates to Taiyin. Taiyin disease typically causes jaundice; if urination is free, jaundice will not occur. After seven or eight days, if stool becomes hard, it is a Yangming disease." This is an example of Taiyin pathogens entering Yangming. Another example: Shaoyin disease lasting six or seven days with abdominal distension and constipation requires urgent purgation, using Dachengqi Tang (Major Order the Qi Decoction); this is Shaoyin pathogens entering the fu organs. The classics state: "Diarrhea with delirium indicates dry feces, suitable for Xiaochengqi Tang (Minor Order the Qi Decoction)." This is Jueyin pathogens entering the fu organs. Cases of Three Yin pathogens transforming into heat and entering fu organs are common and must be carefully observed.

One type is "One Yang receiving Cold." The Sixteen Syndromes of Shanghan mention: "Shanghan with floating pulse, spontaneous sweating, frequent urination, vexation, slight aversion to cold, and leg cramping." This is deficiency-cold caused by pathogens injuring the Bladder meridian, treated effectively with Guizhi Jia Fuzi Tang (Cinnamon Twig Decoction plus Aconite). If a physician sees the syndrome resembles Yangdan syndrome and incorrectly administers Guizhi Tang (Cinnamon Twig Decoction) to attack the exterior, this is an error. Immediately after taking it, the patient develops cold extremities, dry throat, vexation, vomiting, and regurgitation. One should prepare Gancao Ganjiang Tang (Licorice and Dried Ginger Decoction) to restore yang. Once cold extremities resolve and feet warm, prepare Shaoyao Gancao Tang (Peony and Licorice Decoction) to relieve leg cramping. If stomach qi is disharmonious causing delirium, administer a small amount of Tiaowei Chengqi Tang (Regulate the Stomach and Order the Qi Decoction). If excessive sweating is repeated and burning needles are added, Sini Tang (Recover the Extremities Decoction) is indicated. Observing Zhang Zhongjing's treatment of such damaged diseases demonstrates the method of sweating first, then purging. Another example: Diarrhea with undigested food, interior cold with exterior heat, and body pain require urgent rescue of the interior using Sini Tang. Once diarrhea stops, interior harmony is restored, and excretion normalizes, urgently rescue the exterior using Guizhi Tang. This is the method of warming the interior first, then releasing the exterior. Sun Zhao stated: Originally a yang-heat disease, if too much vomiting and purging by physicians turns it into a yin disease, warming is appropriate. Conversely, originally a yin disease, if too many warming medicines cause stomach heat excess or hard stool with狂言 (mad speech), purging is appropriate.

Treatises sometimes refer to "Taiyang Meridian Disease" or "Taiyin Meridian Disease"; sometimes "Shanghan" or "Zhongfeng" (Wind Strike); sometimes only "Jue" (cold extremities) or "Xiali" (diarrhea); sometimes only "Bing" (disease). Referring to a specific meridian implies pathogens struck that meridian, indicating not just Shanghan patterns but also mixed diseases. Referring only to "Shanghan" without specifying a meridian implies non-mixed diseases affecting all six meridians, not confined to one. Zhongfeng diseases are similar. References to "Xiali" and "Jue," or general patient names, imply these symptoms can occur across all six meridians in Shanghan, Zhongfeng, and mixed diseases. He Suhe categorized syndromes into meridians, leading to inaccuracies. For example, diarrhea with delirium and dry feces suitable for Xiaochengqi Tang was categorized under Jueyin diarrhea by He Suhe; symptomatically, it belongs to Yangming. Such errors cause later generations to rigidly adhere to the six meridians, arbitrarily distinguishing cold and heat, deviating from the sage's way.

A skilled healer must carefully distinguish: Is it a pathogen transmitted through the meridians from Taiyang, or a direct strike to various meridians? Are there original syndromes before sweating, vomiting, or purging? Or are there complications like fire reversal, water spraying, chest binding, jaundice, blood stasis, pi-syndrome, diarrhea, or jue? For Zhongfeng, Shanghan, and mixed disease patterns, all illnesses should be distinguished by exterior and interior rather than confined to the six meridians. Generally, all six meridians have exterior and interior aspects. If exterior syndromes exist, sweating is indicated; if interior syndromes exist, purging is indicated. If both exterior and interior syndromes exist, purgatives combined with sweating agents are used, depending on the proportion of exterior versus interior pathology. For half-exterior, half-interior conditions, harmonizing methods are used. This is the treatment for transmitted diseases. For mixed disease cold patterns in the exterior, acrid-warm sweating is used; for cold striking the interior, strong heating agents are used. This merely clarifies exterior and interior, with no other complexity.

Generally, if a syndrome appears after taking medicine that was not present initially, this corresponds to the classics' description of post-emesis, post-sweating, or post-purgation syndromes, known as "Huai Bing" (Damaged Disease). One must treat the resulting deviations. If the initial syndrome persists after taking medicine without new symptoms appearing, the disease has not receded. Zhongjing stated: "If after one dose of decoction the syndrome remains, continue administration; sweating and purging methods are consistent." Mr. Qingbi Du stated: Yang-heat diseases are difficult to treat; yin-cold diseases are easier. Heat transmits and changes unpredictably, while yin-cold does not transmit, having fixed treatment methods. Mr. Ren'an Yan stated: When treating others' Shanghan, one must investigate prior syndromes and medications. If syndromes are mixed, treat the severe ones first, then the mild. For transmitted pathogens, there are three treatments: sweating for those in the skin, harmonizing for those between exterior and interior, and purging for those in the interior. This is treatment from exterior to interior. For deficient individuals engaging in intercourse or irregular diet, leading to interior deficiency and pathogen invasion, sweating from the exterior is inappropriate; strong warming agents are required. The classics state: "Yin struck by pathogens causes internal trembling." Due to slight exterior qi deficiency and loss of interior qi defense, pathogens invade the yin. When interior qi fails and pathogens invade, weak righteous qi causes trembling. The classics state: "Cold injures Ying (Nutrient) blood; cold blood coagulates and stagnates, preventing limb qi-blood connection, causing jue, cold body, and aversion to wind." Fuzi and Ganjiang are appropriate. If cold retreats but heat-toxin attacks internally, causing blurred vision, watery diarrhea, and abdominal fullness, urgent purging is required. This discusses Shaoyin meridian treatment. If cold retreats but extremities remain cold, fluctuating between hot and cold, with abdominal pain and dysuria, Sini San (Recover the Extremities Powder) is used. This refers to Shaoyin transmission being similar to Taiyang.

Generally, treating Shanghan requires syndrome differentiation. If pulse and syndrome match, identification is easy; if they mismatch, urgency must be carefully judged. Neither syndrome nor pulse alone suffices; both must align for perfection. Expert physicians prioritize emergencies in severe cases, sometimes relying solely on syndrome or solely on pulse. For example, the classics state: "Floating and large pulse, hardness below the heart, heat, belonging to zang organs, requires purging, not sweating." This is not a sweating pulse for exterior pathogens. A rapid pulse indicates yang excess; if accompanied by diarrhea, wheezing, and sweating, Gegen Huangqin Huanglian Tang (Kudzu, Scutellaria, and Coptis Decoction) is used. If cold extremities and rapid pulse indicate collapse, moxibustion and warming are essential, not indicating yang excess. A slow pulse in Yangming, without aversion to cold, with body sweating, indicates Dachengqi Tang usage, contradicting the rule that slow pulses indicate cold. Early Shaoyin disease with fever and deep pulse requires Mahuang Xixin Fuzi Tang (Ephedra, Asarum, and Aconite Decoction) for mild sweating, contradicting the rule that deep pulses indicate interior conditions, except when "no aversion to cold" is the key. Although the classics warn "Guizhi swallowed leads to death in yang excess," this is a fixed rule. Delirium with aversion to cold requires Guizhi Tang to resolve the exterior first, then purge, distinguishing exterior-only from interior involvement. This is Zhongjing's method of relying on syndrome over pulse.

The classics state chest binding syndromes require purging, but if the pulse is floating, purging is contraindicated. This differs from fever for 7-8 days with floating-numerous pulse, where purging is allowed. Delirium with tidal fever and slippery-rapid pulse allows Xiaochengqi Tang; if no bowel movement the next day and pulse becomes faint-choppy, further Chengqi Tang is forbidden. This differs from cases where gas passage indicates readiness for purging. Fever, aversion to cold, weak pulse, and delayed chi pulse contraindicate sweating, differing from exterior sweating indications. This is Zhongjing's method of relying on pulse over syndrome.

Pulse reveals disease depth and syndrome inevitability. Agile physicians weigh pulse and syndrome together; once decided, treatment is straightforward. Medical subtlety lies herein.

When classics mention specific yin-yang diseases, one must discern similarities and clarify diagnosis before medicating to avoid errors. The classics state: "Fever with aversion to cold originates in yang; no fever with aversion to cold originates in yin." For Shanghan, whether fever has appeared or not, aversion to cold, body pain, vomiting, and tight pulse indicate subsequent fever, originating in yang. Initial non-fever with aversion to cold resembles yin origin, but differs by headache and stiff neck, absent in yin. Aversion to cold with curling up, deep-tight pulse indicates yin origin. Yang origins allow sweating; yin origins require warming the interior.

Shaoyin deep pulse with initial fever resembles Taiyang but differs: fever is not intense, and headache is absent.

Shaoyin abdominal pain and diarrhea resemble Taiyin but differ: Taiyin lacks thirst, Shaoyin has thirst; distinction lies in warm vs. cold extremities.

Warm disease and Jing (spasm) disease resemble Taiyang but differ: Jing pulse is deep-thin; Warm disease lacks aversion to wind-cold but has thirst.

Shanghan and Zhongfeng (Wind Strike) resemble each other but differ: Wind Strike lacks thirst, Shanghan has thirst. Shanghan and Dongwen (Winter Warmth) differ: Shanghan pulse is floating-tight; Dongwen pulse is not floating.

Epidemic contagion resembles Shanghan but differs: Epidemic pulse is not floating; Shanghan pulse is floating.

Taiyang Zhongshi (Dampness Strike) resembles Taiyang Shanghan but differs: Dampness pulse is deep-thin. Answer: Pulses may seem similar, but Jing differs; Jing has no body pain, Dampness has body pain.

Summerheat pulse is empty-thin, weak, string-thin, hollow-slow. These resemble Jing and Dampness pulses. Though pulses are similar, syndromes differ: Summerheat has spontaneous sweating and thirst; Dampness has no thirst and body pain; Jing has no body pain.

Taiyang Zhongfeng showing cold pulse uses Daqinglong Tang. Resembles Taiyang Shanghan but differs: Zhongfeng with cold pulse has vexation; Mahuang syndrome lacks vexation.

Taiyang Shanghan showing wind pulse uses Daqinglong Tang. Resembles Cold-Damp Strike but differs: Pulse is floating-slow; Cold-Damp pulse is deep-thin-subtle. Classics state "No Shaoyin interior syndrome," as Taiyang and Shaoyin are exterior-interior pairs; current pulse/syndrome belong to Taiyang exterior, hence no Shaoyin interior syndrome.

Xiaoqinglong Tang syndrome resembles Xiaochaihu Tang syndrome but differs: Xiaoqinglong lacks alternating chills/fever and hypochondriac fullness/pain, presenting only dry retching, fever, and cough due to unresolved exterior and fluid retention in the epigastrium. Although optional symptoms resemble Xiaochaihu, the absence of half-exterior/half-interior syndrome distinguishes them.