Dryness is predominant in autumn. So disease caused by dryness mostly appears in autumn. In late summer dampness permeates. But in autumn dampness disappears and the weather becomes cool and dry. Dryness can be divided into warm-dryness and cool-dryness due to difference in weather. The disease occurring at the early stage of autumn is a kind of warm-dryness because there is still some remaining summer-heat; the disease occurring at the late stage of autumn is a kind of cool-dryness syndrome because the weather is already cold in late autumn.

The following is a brief description of the nature and characteristics of dryness in causing disease:

Dryness is usually caused by insufficiency of body fluid. So the attack by dryness tends to consume body fluid and lead to dryness of the mouth and nose, dry throat, dry skin or even rhagas, scanty urine and retention of dry feces.

Dryness is prevailing in autumn and is associated with the lung. So dryness tends to impair the lung when it invades the body. If it impairs the lung, the lung-fluid will be consumed and the function of the lung to depurate and descend will be affected, leading to dry cough with scanty phlegm, or sticky sputum difficult to expectorate, or blood sputum, dyspnea and chest pain.