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First, distinguish the difference in pathogenic qi. Wind primarily governs dispersion and leakage, while cold primarily governs coagulation and stagnation. Although these two types of qi differ, initially both are cold rather than hot. When they invade the human body, they cause stagnation without dissemination; therefore, when the pathogen is initially at the exterior level, it is appropriate to use warming and dispersing methods. Formulas such as Mahuang Tang (Ephedra Decoction), Guizhi Tang (Cinnamon Twig Decoction), Gegen Tang (Kudzu Root Decoction), and Suqiang Yin (Perilla and Notopterygium Drink) are all agents for dispersing cold, not for resolving heat. Warm-heat diseases arise from latent pathogens transforming into heat; they are hot rather than cold. When they damage the body, they immediately cause steaming and putrefaction, so cooling and resolving methods should be used from the onset. Formulas such as Zhichi Tang (Gardenia and Fermented Soybean Decoction), Gegen Qinlian Tang (Kudzu Root, Scutellaria, and Coptis Decoction), Maxing Shigan Gao (Ephedra, Apricot Kernel, Gypsum, and Licorice Paste), Huangqin Tang (Scutellaria Decoction), Weirui Tang (Polygonatum and Cistanche Decoction), and Liushentongjie San (Six Spirits Unblocking and Releasing Powder) are all agents for resolving heat, not for dispersing cold. Using heat-resolving agents to treat wind-cold may, in mild cases, lead to cold damaging the middle jiao causing vomiting and diarrhea; in severe cases, it may lead to sinking of yang and reversal cold (Jue Ni). Using cold-dispersing agents to treat warm-heat may, in mild cases, lead to epistaxis, thirst, delirium, and madness; in severe cases, it may lead to exhaustion of yin fluids and collapse of yin. This is why the nature of the pathogenic qi must be distinguished.

Second, distinguish the difference in the mode of invasion. Wind-cold enters from the exterior to the interior, progressing layer by layer from the skin and hair pores to the muscle interstices, then to the sinews and bones, and finally to the chest, diaphragm, stomach, and intestines. It cannot skip layers to enter directly; thus, sweating should not be delayed excessively, and purgation should not be initiated too early. Whether using dispersing or harmonizing methods, the depth of treatment must not be confused. Because the qi of wind-cold is cold, one must wait for the cold to transform into heat and for the pathogen to retreat inward before employing purgative and cooling methods; otherwise, the interior qi will be weakened, potentially drawing the exterior pathogen inward and resulting in conditions such as Jie Xiong (chest binding), Pi Li (fullness and diarrhea). Damp-warmth emerges from the Mo Yuan (membrane source), and warm-heat emerges from the blood collaterals. They first occupy the interior of the membrane and collaterals, requiring internal breakdown before manifesting the "Nine Transmissions." Although emerging from the interior to the exterior, even when at the exterior level, the interior may not be entirely free of lingering pathogen, and the semi-exterior/semi-interior levels traversed may also be injured by the pathogen. Therefore, purgation should not be delayed excessively, and sweating should not be initiated too early. Whether using harmonizing or resolving methods, the depth of treatment must not be rigidly adhered to. Because the qi of warm-heat is hot, heat generates steaming without needing the stagnation-transformation process required by cold; this steaming inherently carries heat from other areas. If warming agents are mistakenly used before the pathogen has exited the exterior, it will initially cause the heat toxin to spread like a prairie fire, leading to macules, epistaxis, mania, and panting; in the final transmission, it damages true yin, leading to critical conditions such as withering, coma, and reversal cold.

Third, distinguish the difference in meridian transmission. The transmission of warm-heat differs from that of wind-cold. Wind-cold moves from the exterior to the interior, necessarily transmitting from the Taiyang (Greater Yang) channel to the Yangming (Yang Brightness) channel, then to the Shaoyang (Lesser Yang) channel, and finally entering the Stomach. In contrast, warm-heat pathogens originate from the Middle Dao (Middle Jiao/Spleen-Stomach region) and may appear in the exterior or interior, depending on the strength or weakness of the patient's meridians for transmission. Thus, when latent pathogens erupt, there are cases of exterior preceding interior, interior preceding exterior, interior only without exterior, exterior recurring after initial resolution, interior recurring after initial resolution, predominance of either exterior or interior, simultaneous transmission of exterior and interior, repeated simultaneous transmission, and simultaneous eruption of exterior, interior, and the Three Jiao. These are termed the "Nine Transmissions." Physicians must understand the rationale behind the Nine Transmissions to treat latent pathogens. To summarize: Wind-cold transmits from exterior to interior, requiring gradual closure and stagnation before transmission; thus, during the exterior stage, interior symptoms need not be present, and after entering the interior, exterior symptoms need not reappear. Warm-heat originates from the interior emerging to the exterior; therefore, when exterior symptoms appear, they are invariably accompanied by one or two interior symptoms, and also by one or two semi-exterior/semi-interior symptoms. Moreover, warm-heat belongs to vapor-like qi, where the transition between exterior and interior is not fixed. There are cases where interior symptoms are treated with purgatives but the pathogen remains incomplete and can still emerge to the exterior; there are cases where, after delirium and coma, the illness subsides for several days, only to reappear with headache and fever, resolving again through sweating. This is called "exterior recurring," which never happens with wind-cold. Furthermore, there are cases where all purgative indications are present; after using purgatives, the interior qi becomes unblocked and the exterior qi also reaches the surface, with headache and fever resolving through sweat, and chest fullness and irritability temporarily resolving through rashes and macules. However, after a short time, black tongue, chest oppression, abdominal pain, and delirium reappear, requiring massive purgation to heal. This is called "interior recurring," which also never happens with wind-cold. Regarding symptoms of simultaneous exterior-interior transmission and Three Jiao eruption, these occur in less than 10-20% of wind-cold cases but in 60-70% of warm-heat cases. Differentiation relies solely on whether the transmission is specific or mixed. Initial presentation of symptoms in a single meridian indicates wind-cold; initial presentation of mixed symptoms in two or three meridians indicates warm-heat. Gradual transmission over many days indicates wind-cold; sudden transmission involving one to three meridians within a day indicates warm-heat. Thus, although diseases may vary in manifestation, wind-cold will not be confused with warm-heat, nor warm-heat with wind-cold, ensuring accurate treatment.