Diseases with fever and chills are caused by yang; those without fever but with aversion to cold are caused by yin. Those caused by yang will heal in seven days; those caused by yin will heal in six days. This is because the number for yang is seven and the number for yin is six.

bubble_chart Note

• The diseases referred to are apoplexy and cold-damage disease.
• Some diseases start with fever and aversion to cold, which are called apoplexy and are caused by the defensive yang.
• Some diseases start without fever but with aversion to cold, which are called cold-damage disease and are caused by the nutritive yin.
• Those caused by yang will heal in seven days, and those caused by yin will heal in six days, because yang corresponds to the number seven and yin corresponds to the number six.

bubble_chart Collected Annotations

• Fang You-zhi said: "This explains the origin of apoplexy and cold-damage disease, and the reason for their eventual healing. All diseases in the taiyang stage involve aversion to cold. 'Fa' means onset, and 'yu' means recovery."
• Cheng Zhi said: "This distinguishes the reasons for fever and absence of fever in taiyang disease. Wind is yang, and the defensive qi is also yang; cold is yin, and the nutritive qi is also yin. Apoplexy and cold-damage disease are both exterior syndromes. When wind enters the defensive qi, the pathogen arises from yang and causes fever; when cold enters the nutritive qi, the pathogen arises from yin and does not immediately cause fever. Yang moves quickly, so it often transmits from one meridian to another and heals one day later; yin moves slowly, so it often follows the meridians and heals one day earlier. Observing this, the distinction between wind and cold becomes clear."
• Wei Li-tong said: "Wind damages the defensive qi, and cold damages the nutritive qi. Since both are in the taiyang stage, there is no absence of fever, but the speed varies. As for aversion to cold, it is the same. The meaning of arising from yang and arising from yin simply refers to wind being yang and the defensive qi also being yang; cold being yin and the nutritive qi also being yin. It does not extend to the three yin stages."