Yellow Emperor asked: The origin of all diseases must arise from dryness and dampness, cold and heat, wind and rain, yin and yang imbalance, excessive emotions (anger and joy), improper diet, and living conditions. When these pathogenic factors combine with the body's qi, they form specific pathological manifestations; once they enter the zang-fu organs, they acquire specific names. I understand this principle. However, why do many diseases present with clarity in the morning, stability during the day, aggravation in the evening, and severity at night?

Qibo replied: This is caused by the influence of the seasonal qi.

Yellow Emperor said: I wish to hear about the qi of the four seasons.

Qibo said: Spring generates, Summer grows, Autumn harvests/converges, and Winter stores/closes. This is the normal pattern of qi. Humans also respond to it. If we divide a day into four parts corresponding to the seasons, then morning corresponds to Spring, midday to Summer, sunset to Autumn, and midnight to Winter. In the morning, the healthy qi of the human body begins to generate, and the pathogenic qi declines, so there is clarity in the morning. At midday, the healthy qi grows; when it is strong, it overcomes the pathogenic factors, so there is stability during the day. In the evening, the healthy qi begins to decline, and the pathogenic qi begins to generate, so the condition aggravates. At midnight, the healthy qi enters the zang organs, leaving the pathogenic qi to dominate the body alone, so the condition is most severe.

Yellow Emperor asked: Why are there sometimes reverse situations?

Qibo said: This occurs when one does not conform to the seasonal qi, and the disease is dominated solely by the zang organs. In such cases, the condition will definitely worsen during the time/season that is overcome by the zang qi (i.e., the element controlled by the organ) and improve during the time/season that overcomes the zang qi (i.e., the element controlling the organ).

Yellow Emperor asked: How should it be treated?

Qibo said: By conforming to the heavenly timing, the disease can be anticipated and cured. Those who conform are skilled physicians; those who go against are crude physicians.

Yellow Emperor said: Excellent.

It is better to nurture health before illness arises than to treat after illness has occurred. Treating with medicine after the disease has formed is merely futile labor. Therefore, treating after the disease has formed is the standard method of physicians; intervening before the disease forms elucidates the principles of life preservation. If one can thus think of potential troubles and prevent them beforehand, what troubles would there be to worry about? This is the meaning behind the Sages' principle of "treating disease before it arises" rather than treating it after it has arisen.

I have said that using earth to block water, if one does not seal the trickling streams, the overwhelming flood cannot be stopped; using water to fight fire, if one does not extinguish the faint spark, the prairie fire cannot be halted. If the momentum of water and fire, once vigorous, cannot be stopped, how much less can an already established disease be cured? Therefore, in the spring of "releasing and growing," one should sleep late and rise early; in the summer of "flourishing and beauty," one should rise early and sleep late. One should relax the body, avoid anger, and fulfill one's will, consuming cool and cold foods to nourish yang. Thus did the Sages prevent disease in spring and summer. In the autumn of "maturity and peace," one should rise with the rooster; in the winter of "hiding and storing," one should wait for sunlight to rise. One should gather the spirit, conceal the will, and conserve intent, consuming warm and hot foods to nourish yin. Thus did the Sages prevent disease in autumn and winter.

Someone asked: Seeing liver disease, first strengthen the deficiency of the spleen, so that wood pathogens cannot transmit; seeing redness on the right cheek, first drain the heat of the lung meridian, so that metal pathogens cannot flourish. This is the method of treating disease before it arises. Now, you propose preventing disease by conforming to the four seasons and regulating the spirit. What is the meaning of this?

Commentary by Xu Chunfu: Preserving the body intact for longevity is the Way of the Sages; achieving ten out of ten cures is the technique of superior physicians. The saying "treat disease before it arises" is recorded in the *Su Wen: Treatise on Regulating the Spirit According to the Four Qi*. Its purport is profound! In the ancient dialogues between the Yellow Emperor and the Heavenly Master, emphasis was always placed on nurturing and preservation first, discussing primordial truth initially, and regulating the spirit subsequently. Having learned to follow yin and yang, one proceeds to regulate according to the four qi; having emphasized moderation in diet, one follows with regularity in daily routine. Urgently stressing health preservation, the intention was to treat diseases before they occur, preventing them from becoming difficult to manage once established. Later, Qin Huan (Bian Que) understood this principle. Seeing the Duke of Jin's disease had reached the epigastrium and diaphragm, he said, "It cannot be cured." Bian Que, understanding this, saw the Duke of Qi's disease had penetrated to the bone marrow and declared, "It cannot be saved." Alas! It is a pity that the Dukes of Qi and Jin did not understand the principle of treating disease before it arises. (Commentary by Zhu Danxi)