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The *Huangdi Neijing* (Yellow Emperor's Inner Canon) discusses malaria (*Nue*, Malaria), often attributing it to wind, cold, summer-heat, and dampness. However, wind and summer-heat are yang pathogens, while cold and dampness are yin pathogens. The cause of illness is mostly due to summer-heat injury in summer, where excessive sweating causes the couli (pores) to open. If one encounters cold water during this time, cold pathogens first lie latent in the skin. When autumn arrives, the new coolness binds the exterior, preventing the exterior pathogens from dispersing outward. Consequently, yin desires to enter but yang rejects it; yang desires to exit but yin obstructs it. The struggle between yin and yang leads to the onset of disease.

The symptoms generally manifest as alternating chills and fever, or only chills without fever, or only fever without chills, or chills preceding fever, or fever preceding chills. There may be sweating or no sweating, or varying degrees of sweat. Other symptoms include headache and bone pain, extreme thirst with a desire to drink, vomiting and loss of appetite, irritability and insomnia, dry and constipated stools, or abdominal fullness with diarrhea and dysentery. When the pathology is shallow, it resides in the Three Yang meridians and moves in and out with the Wei Qi (Defensive Qi), resulting in daily attacks. When the pathology is deep, it resides in the Three Yin meridians, and the pathogenic factor cannot exit together with the Wei Qi, resulting in attacks every other day or every three to four days. The later the attack occurs, the deeper the pathology. Therefore, the severity of malaria depends on the depth and superficiality of yin and yang. In the *Shennong Bencao Jing* (Divine Farmer's Materia Medica), there are distinctions among cold malaria, warm malaria, and dan malaria, as well as classifications according to the Six Meridians and Five Zang Organs, providing comprehensive and exhaustive explanations.

Zhu Danxi further distinguished cases based on food stagnation, fluid retention, phlegm-fluid, and blood stasis. These are merely concurrent syndromes of malaria, not the primary causes of malaria itself. Additionally, zhang malaria arises from the miasma and dampness of the Lingnan region. Pin malaria (yin-type malaria) commonly occurs in individuals with insufficient yang qi. Lao malaria (labor-induced malaria) results from deficiency of qi in both the interior and exterior, triggered by overexertion. Gui malaria (ghost malaria) involves no actual "ghost," but rather pathogenic factors disturbing the spirit (Shen).

Therefore, when treating malaria, one must examine the depth of the pathogen and differentiate the yin-yang nature of the syndrome. The treatment should aim to guide the pathogen from the Zang organs to the Fu organs, from the interior to the exterior, from yin to yang, and shift the timing of attacks from late (yan) to early (zao). By guiding and dispersing the pathogen, and lifting and raising the healthy qi, the pathogen can be expelled, leading to natural harmony. Regarding syndromes such as phlegm-food retention, blood-qii obstruction, internal cold, and internal heat, these should be treated concurrently based on their severity, but they should not be the primary focus for tonification. However, when the pathogen is in the Yang meridians, inducing sweating is easy; when the pathogen is in the Yin meridians, inducing sweating is difficult. Furthermore, if heat predominates, cooling herbs are effective; if cold predominates, warming herbs are primary. In cases where external wind-cold and internal damage from raw/cold foods lead to deficiency in both the exterior and interior, causing simultaneous malaria and dysentery, since the malaria pathogen enters via the meridians and the dysentery pathogen affects the zang organs, treating both the exterior and interior simultaneously will gradually resolve the root cause of damp-warmth, leading to recovery.